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COVID-19: Infection prevention for persons with SARS-CoV-2 infection

COVID-19: Infection prevention for persons with SARS-CoV-2 infection
Authors:
Tara N Palmore, MD
Becky A Smith, MD
Section Editor:
Daniel J Sexton, MD
Deputy Editor:
Jennifer Mitty, MD, MPH
Literature review current through: Jul 2022. | This topic last updated: Jun 23, 2022.

INTRODUCTION — At the end of 2019, a novel coronavirus was identified as the cause of a cluster of pneumonia cases in Wuhan, a city in the Hubei Province of China. It rapidly spread, prompting the World Health Organization (WHO) to declare a public health emergency in late January 2020 and characterize it as a pandemic in March 2020. The virus that causes COVID-19 is designated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Understanding of COVID-19 is evolving. Interim guidance has been issued by the WHO and by the United States Centers for Disease Control and Prevention [1,2]. (See 'Society guideline links' below.)

This topic will provide an overview of infection prevention issues when caring for patients with suspected or confirmed COVID-19.

General infection prevention policies and procedures in the health care setting during the COVID-19 pandemic (eg, screening, universal masks, care for patients without suspected COVID-19) are discussed in a separate topic review. (See "COVID-19: General approach to infection prevention in the health care setting".)

Other topics that pertain to COVID-19 and infection prevention include:

(See "COVID-19: Management of the intubated adult".)

(See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control".)

(See "COVID-19: Clinical manifestations and diagnosis in children" and "COVID-19: Clinical manifestations and diagnosis in children", section on 'Introduction'.)

(See "COVID-19: Overview of pregnancy issues".)

(See "COVID-19: Arrhythmias and conduction system disease".)

(See "COVID-19: Myocardial infarction and other coronary artery disease issues".)

(See "COVID-19: Issues related to acute kidney injury, glomerular disease, and hypertension".)

INFECTION PREVENTION IN THE HEALTH CARE SETTING — Infection prevention interventions to reduce transmission of SARS-CoV-2 include universal source control (eg, covering the nose and mouth to contain respiratory secretions), early identification and isolation of patients with suspected disease, the use of appropriate personal protective equipment (PPE) when caring for patients with COVID-19, hand hygiene, and environmental disinfection. Discussions of screening and universal use of masks are presented elsewhere. (See "COVID-19: General approach to infection prevention in the health care setting", section on 'Screening prior to and upon entry into the health care facility' and "COVID-19: General approach to infection prevention in the health care setting", section on 'Universal use of masks'.)

Limiting transmission of SARS-CoV-2 is an essential component of care in patients with suspected or documented COVID-19. In an early report of COVID-19 in 138 patients from China, it was estimated that 43 percent acquired infection in the hospital setting [3]. In Washington State, suboptimal use of infection prevention procedures contributed to the spread of infection to 81 residents, 34 staff members, and 14 visitors in one long-term care facility [4].

However, the exact risk of acquiring COVID-19 in the health care setting remains unclear. As an example, while some reports have found a higher proportion of COVID-19 cases among health care personnel (HCP) in patient-facing roles [5], others have found that infection rates among HCP often appear to parallel those of the general population [6-10]. In a serologic survey of 10,275 HCP, factors most strongly associated with seropositivity were contact with a person with known or suspected COVID-19 outside the workplace (adjusted odds ratio [aOR] 1.9, 95% CI 1.4-2.6), being of a Black population (aOR 2.1, 95% CI 1.7-2.6), and the incidence of COVID-19 in the community (aOR 1.5, 95% CI 1.0-2.2) [8]. In this study, HCP who cared for patients with COVID-19 and those who worked in areas where aerosol-generating procedures were routinely done were not more likely to be seropositive, but these estimates were imprecise.

General approach — This section will review the infection prevention precautions that should be used when caring for patients with suspected or confirmed COVID-19. (See 'Type of room' below and 'Type of PPE' below and 'Transporting patients outside the room' below.)

The same infection prevention policies and precautions should be used for HCP and patients who have received one of the available COVID-19 vaccines [11]. Cases of SARS-CoV-2 infection have been reported in fully vaccinated HCP, and there are higher rates of breakthrough infections with certain variants (eg, Omicron), which have become the dominant variants in many countries at various points during the pandemic. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Risk of reinfection' and "COVID-19: Epidemiology, virology, and prevention", section on 'Variants of concern'.)

Similarly, the approach to infection prevention should be the same for those with prior COVID-19. Although the risk of reinfection within the first three months after having COVID-19 is low, cases of probable reinfection with SARS-CoV-2 during this time frame have been reported, particularly with the Omicron variant. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Risk of reinfection'.)

In areas of ongoing transmission, enhanced infection prevention precautions (eg, respirators for aerosol-generating procedures, eye protection [eg, face shields] in addition to universal masking) should be used when caring for all patients, regardless of the individual suspicion for COVID-19. This is discussed in detail elsewhere. (See "COVID-19: General approach to infection prevention in the health care setting", section on 'Precautions for those NOT suspected of having COVID-19'.)

Type of room — Patients should be placed in a well-ventilated single-occupancy room with a closed door and dedicated bathroom [11,12]. When this is not possible, patients with confirmed COVID-19 can be housed together; for patients who are antigen positive, the diagnosis should be confirmed with a nucleic acid amplification test (NAAT). (See "COVID-19: Diagnosis", section on 'Specific diagnostic techniques'.)

An airborne infection isolation room (AII; ie, a single-patient, direct out-exhausted air, >6 to 12 air exchanges per hour, negative-pressure room) should be prioritized for patients undergoing aerosol-generating procedures. Additional information on AII rooms and what to do when these are not available is found below. (See 'Aerosol-generating procedures/treatments' below.)

Patients with COVID-19 should not be placed in a positive-pressure room.

Type of PPE — All HCP who enter the room of a patient with suspected or confirmed COVID-19 should wear personal protective equipment (PPE) to reduce the risk of exposure.

Standard PPE for patients with suspected or confirmed COVID-19 includes the use of a gown, gloves, ideally a respirator (minimally, a medical mask), and eye or face protection:

Gown and gloves – Isolation gowns and nonsterile gloves should be put on upon entry into the patient room or area. Caregivers should perform hand hygiene after removing and before putting on gloves.

Some institutions require double gloving for HCP caring for patients with suspected or confirmed COVID-19 to reduce the risk of skin contamination when doffing. However, there are insufficient data to support the routine use of double gloving. Although experimental data suggest double gloving may reduce skin contamination with viral particles [13], it remains unclear whether this further reduces transmission. In addition, the practice may have unintended consequences if guidelines are not followed strictly. As an example, in one report, the practice of double gloving on a COVID-19 unit was implicated in an outbreak of Candida auris [14].

On COVID-19 units, gowns do not need to be routinely changed between patients unless the gown is soiled or the patient requires additional contact precautions (eg, for a drug-resistant organism), in which case a new gown should be used. However, gowns and gloves should not be worn into common spaces (eg, workstations).

Respirator or medical mask – A National Institute for Occupational Safety and Health (NIOSH)-approved respirator should be worn instead of a medical mask (eg, surgical mask) during aerosol-generating procedures and certain types of environmental cleaning. (See 'Aerosol-generating procedures/treatments' below and 'Environmental disinfection' below.)

Guidelines differ somewhat regarding the use of a medical mask or a respirator for other types of care [11,15-18]. As an example, the United States Centers for Disease Control and Prevention (CDC) recommends a respirator when caring for all patients with suspected or confirmed COVID-19; medical masks are an acceptable alternative for routine care only when the supply of respirators is severely limited [19]. The World Health Organization (WHO) states that a medical mask may be sufficient in the absence of aerosol-generating procedures but states that a respirator should be worn in care settings where ventilation is known to be poor or cannot be assessed or where the ventilation system is not properly maintained. It also acknowledges that providers may prefer a respirator based on their preferences and on their perception of what offers the highest level of protection to prevent SARS-CoV-2 infection [18]. Both guidelines agree that cloth masks are not considered sufficient PPE for HCP and should not be worn for the care of patients.

When a respirator is used, most HCP use disposable N95 respirators. However, those who have beards or who cannot be medically cleared or fit tested for N95 use should wear a powered air-purifying respirator (PAPR), which comes in various models and styles and offers a high level of protection. Respirators with an exhalation valve or vent should not be used since they do not provide source control; however, if there are shortages of PPE and this type of respirator is used, a medical mask should be placed on top of it for source control. (See "COVID-19: General approach to infection prevention in the health care setting", section on 'Universal use of masks'.)

There are no data to suggest a medical mask worn over an N95 provides additional respiratory protection for the HCP, but this practice may allow for extended use of PPE in some settings. Detailed discussions of universal masking and extended use and reuse of masks and respirators are presented elsewhere. (See "COVID-19: General approach to infection prevention in the health care setting", section on 'Universal use of masks' and 'When PPE is limited' below.)

There are limited data comparing the use of respirators or medical masks when caring for patients with suspected or confirmed COVID-19 [20,21]. We agree with CDC recommendations and suggest the use of respirators when caring for all patients with suspected or confirmed COVID-19, since there is evidence that airborne transmission may occur [11,22,23], especially high-velocity, small-particle aerosols generated by coughing and sneezing, with particles that remain airborne for longer and travel farther than usual respiratory droplets. In addition, limited data suggest respirators may provide additional protection when caring for those with COVID-19 [24-26]. More detailed information on transmission of SARS-CoV-2 is presented elsewhere. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Route of person-to-person transmission'.)

In all cases, the mask should be well fitting to improve source control and protection of the wearer from infectious particles [11]. An experimental study by the CDC suggested even greater protection to the wearer from adjusting the fit of a surgical mask using mask extenders, knotting the ear loops, or tucking in the side folds to reduce gaps around the mask [27]. In one report, surgical masks with head ties had greater fitted filtration efficiencies than a procedure mask with ear loops (71.5 versus 38.1 percent, respectively) [28].

Eye or face protection – For eye or face protection, goggles or a face shield that covers the front and sides of the face should be used in conjunction with a respirator or medical mask, as discussed above; glasses are not sufficient. However, if a PAPR is used, additional eye protection is not needed.

When caring for patients with suspected or confirmed COVID-19, we prefer that HCP wear a full-face shield, rather than goggles or a surgical mask with an attached eye shield, whenever possible. A full-face shield provides eye protection and a double layer of protection for the nose and mouth. It also prevents contamination of the respirator or mask. Full-face shields may be reused as long as they can be adequately cleaned with an approved disinfectant. (See 'Optimizing the supply of PPE' below.)

Some institutions also require hair and shoe covers for providers when caring for patients with COVID-19 outside of the operating room setting (eg, on a dedicated COVID-19 ward or intensive care unit). However, there are insufficient data to make these practices mandatory for routine care. As an example, reports suggest that SARS-CoV-2 RNA can be widely distributed on surfaces, such as floors, particularly in the intensive care unit, and can be found on shoes after intubation [29,30], but whether this reflects infectious virus remains unknown.

HCP should pay special attention to the appropriate sequence of putting on (figure 1) and taking off (figure 2) PPE and the use of hand hygiene to avoid contamination. Videos demonstrating the proper donning and doffing of PPE are available. Errors in removal of PPE are common, even by trained clinicians, and are associated with contamination of HCP with pathogens [31]. This can result in indirect (secondary) transmission. In a Cochrane review that evaluated methods to increase compliance with donning and doffing of PPE, several interventions appeared to have some benefit in preventing contamination, including the use of CDC protocols and face-to-face training [32]. Some institutions have trained PPE observers to provide additional safety during PPE donning and doffing; however, it is unclear whether the presence of trained PPE observers on COVID-19 wards reduces HCP infections related to indirect transmission events.

Although data are limited, available evidence generally supports these PPE recommendations [20,33-40]. In a meta-analysis of observational studies evaluating the risk of transmission of SARS-CoV-2, SARS-CoV, and Middle East respiratory syndrome coronavirus (MERS-CoV), use of medical masks or respirators (aOR 0.15) and eye protection (aOR 0.22) were each associated with a reduced risk of infection [34]. In one study, there was no evidence of SARS-CoV-2 transmission (based upon nucleic acid and serologic testing) in a group of 420 HCP who were provided with appropriate PPE, all of whom had direct contact with COVID-19 patients and performed at least one aerosol-generating procedure [35].

Transporting patients outside the room — Patients with confirmed or suspected COVID-19 should wear a medical mask if being transported out of the room (eg, for studies that cannot be performed in the room). If a portable tent system with high-efficiency particulate air (HEPA) filtration is used to transport patients with COVID-19, the patient does not need to wear a mask, but HCP transporting the patient should wear PPE in case of a failure of the powered HEPA filtration.

Approach in select settings

Aerosol-generating procedures/treatments — In patients with COVID-19, aerosol-generating procedures and treatments should be avoided when possible to reduce the potential risk of transmission to HCP.

Aerosol-generating procedures – In patients with COVID-19, aerosol-generating procedures assumed to be associated with an increased risk of infection typically include (listed alphabetically):

Bronchoscopy (including mini bronchoalveolar lavage)

Cardiopulmonary resuscitation

Filter changes on the ventilator

High-flow oxygen

Manual ventilation before intubation

Nasal endoscopy

Noninvasive ventilation

Open suctioning of airways

Tracheal intubation and extubation

Tracheotomy

Upper endoscopy (including transesophageal echocardiogram)

Swallowing evaluation

Chest physiotherapy

Nebulizer treatments

However, there are poor consensus and poor quality of scientific evidence as to what constitutes an aerosol-generating procedure and the level of risk posed by such procedures. Out of an abundance of caution, some society guidelines have categorized other types of procedures (eg, certain laparoscopic procedures) as aerosol-generating procedures that could increase the risk of SARS-CoV-2 transmission [41,42]. However, the risk of transmission from procedures that do not directly involve the respiratory tract is unclear. A more detailed discussion of SARS-CoV-2 transmission from nonrespiratory sites is presented elsewhere. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Route of person-to-person transmission'.)

Aerosol-generating treatments – Aerosol-generating treatments typically include nebulized medications, thus inhaled medications should be administered by metered-dose inhaler when feasible, rather than through a nebulizer, to avoid the risk of aerosolization of SARS-CoV-2 through nebulization.

If avoiding aerosol-generating procedures or use of a nebulizer is not possible, appropriate PPE for HCP includes use of N95 or other respirators (eg, a PAPR) that offer a higher level of protection [11,12,18,43,44]. Other precautions include eye protection (eg, a face shield that covers the front and sides of the face or goggles), gloves, and a gown. (See 'Type of PPE' above.)

Aerosol-generating procedures should take place in an AII whenever possible. These are single-patient rooms at negative pressure relative to the surrounding areas, direct out-exhausted air, and with a minimum of six air changes per hour (12 air changes per hour are recommended for new construction or renovation). When an AII room is not available, a portable HEPA unit can be placed in the room (ideally between the patient and the door), although it does not compensate for the absence of negative air flow. In one institution, a negative-pressure canopy was used for patients receiving continuous positive airway pressure (CPAP), high-flow nasal cannula, and noninvasive ventilation [45]. Special considerations for aerosol-generating procedures in the operating room are discussed elsewhere. (See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control".)

After an aerosol-generating procedure, HCP and other personnel (eg, environmental services, maintenance) should not enter the room without appropriate PPE (eg, gown, gloves, respirator, eye protection) until sufficient time has passed to allow for removal of infectious particles. The rate of removal depends upon the number of air exchanges per hour, as described on the CDC website [46].

Specimen collection for respiratory viral pathogens — In the setting of the COVID-19 pandemic, respiratory specimens for viral pathogens should be obtained in a single-occupancy room with the door closed, and visitors should not be present during specimen collection. Nasopharyngeal or oropharyngeal specimen collection is not considered an aerosol-generating procedure that warrants an airborne infection isolation room.

When collecting a nasopharyngeal or oropharyngeal specimen in a patient with suspected or confirmed COVID-19, the CDC recommends that HCP in the room wear an N95 or higher level respirator (or medical mask if a respirator is not available), eye protection (eg, face shield or goggles), gloves, and a gown [47]. As noted above, the CDC suggests using a respirator rather than a medical mask when caring for all patients with suspected or confirmed COVID-19. However, when supplies are limited, respirators should be prioritized for aerosol-generating procedures. (See 'General approach' above and 'Aerosol-generating procedures/treatments' above.)

Drive-up testing centers have proliferated as a standard setting in which to conduct testing for SARS-CoV-2. They offer the advantage of high throughput and minimal contact with symptomatic individuals, as patients remain in their cars and undergo sample collection by staff who are wearing PPE.

Additional considerations

Patients who have had an exposure to COVID-19 — Some patients who require hospitalization for a reason unrelated to COVID-19 may have had close contact with someone with suspected or confirmed COVID-19, including during the 48 hours prior to that person developing symptoms or testing positive. (See "COVID-19: Clinical features", section on 'Incubation period'.)

All symptomatic patients should be treated as if they have COVID-19, pending additional evaluation. (See 'General approach' above.)

For asymptomatic patients, recommendations for quarantine in the health care setting can differ from those in the community. The approach to quarantine in these settings is presented elsewhere. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Post-exposure management' and "COVID-19: General approach to infection prevention in the health care setting", section on 'Patients who have had an exposure to COVID-19'.)

Patients with prior COVID-19 — Some patients have recovered from COVID-19 and have met criteria for discontinuation of precautions, as described below (see 'In the health care setting' below), but are subsequently rehospitalized. Precautions for such patients depend on the presence of symptoms and the duration of time since the prior illness.

If the onset of prior illness (or the initial positive test in those who were asymptomatic) was within the last 90 days, we use the following approach:

Patients who are asymptomatic – For most patients who had confirmed SARS-CoV-2 infection within the prior 90 days and are without symptoms of COVID-19, routine screening for SARS-CoV-2 (eg, upon entry to the hospital) is not recommended, and enhanced infection prevention precautions specific for COVID-19 are not required.

An exception may be asymptomatic patients with recent COVID-19 who are severely immunocompromised. This includes allogeneic hematopoietic stem cell transplant recipients, chimeric antigen receptor T (CAR-T) cell therapy recipients, patients with primary or secondary/acquired immunodeficiency disorders, solid organ transplant recipients, and patients receiving B-cell-depleting therapies. For such patients, the use of testing and enhanced infection prevention precautions must be individualized in consultation with an infection diseases specialist since prolonged viral shedding and/or clinical recrudescence have been reported, as discussed below. (See 'Immunocompromised patients with confirmed infection' below.)

In addition, as new variants emerge, this approach may be modified, and local institutional policies may vary.

The need for quarantine in asymptomatic patients with recent COVID-19 after a new exposure is discussed separately. (See "COVID-19: General approach to infection prevention in the health care setting", section on 'Patients who have had an exposure to COVID-19'.)

Patients with symptoms – If the patient has symptoms consistent with COVID-19, we use infection prevention precautions for patients with suspected COVID-19 pending the initial evaluation. Reinfection with SARS-CoV-2 within this time frame can occur, especially with the Omicron variant, which can reinfect those who have had past infection with the Delta or other variants. More detailed discussions of reinfection are presented elsewhere. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Risk of reinfection' and "COVID-19: Diagnosis", section on 'Diagnosis of reinfection'.)

If the onset of prior illness was more than 90 days ago, the patient should be managed similarly to patients without prior COVID-19.

When PPE is limited — Limited availability of personal protective equipment (PPE) has complicated medical care of patients with suspected or documented COVID-19 (and other transmissible conditions) worldwide. The CDC has made a spreadsheet available that facilities can use to calculate their "burn rate," or average daily usage rate for PPE, using the change in inventory.

Optimizing the supply of PPE — In the United States, the CDC offers guidance on optimizing the supply of PPE when sudden increases in patient volume threaten a facility's PPE capacity [17].

Strategies include:

Canceling nonurgent procedures or visits that would warrant use of PPE and favoring home care rather than hospitalization when appropriate.

Increasing the use of telehealth services for outpatients, when appropriate.

Limiting movement outside the patient's room, prioritizing the use of certain PPE for the highest risk situations (eg, aerosol-generating procedures), and designating entire units within a facility to care for known or suspected patients with COVID-19 (ie, cohorting).

Minimizing face-to-face encounters with the patient, which can be done by excluding nonessential personnel and visitors, limiting the number of people who examine the patient, using medications with extended intervals to reduce nursing encounters, and allowing certain types of consultants or other clinical providers (eg, dieticians) to perform telephone interviews with hospitalized patients. In some facilities, patients can convey needs to providers using tablets or other electronic interfaces, further reducing some in-person interactions.

Utilizing alternatives to N95s, such as elastomeric half-mask and full-facepiece air-purifying respirators, as well as PAPRs [48-50]. If the elastomeric respirator has a valve, a medical mask must be placed over it for source control.

Extended or limited reuse of PPE — Extended or limited reuse of PPE is reasonable in certain situations. As an example, some hospitals encourage users to disinfect, store, and reuse face shields unless they become visibly soiled or no longer fit. When a face shield is used for repeated encounters with different patients, the provider should not touch or remove the face shield between patient encounters. The provider should perform hand hygiene before removing the face shield, and the face shield should be disinfected with an Environmental Protection Agency (EPA)-registered product and stored in a clean container.

Similarly, the same medical mask can be used for repeated close contact encounters with several different patients (assuming it is not visibly damaged or soiled) but should be changed between use on patients with suspected or confirmed COVID-19 and patients without COVID-19 [51]. When a mask is used for repeated encounters, the provider should not touch or remove the mask between patient encounters, since the outside surface is presumably contaminated. If the provider does touch the mask, they must immediately perform hand hygiene. The CDC suggests that masks can be used for 8 to 12 hours [51], whereas the WHO states medical masks can be used for up to six hours when caring for a cohort of patients with COVID-19 [52].

Extended use and reuse of N95 respirators have also been implemented in many hospital settings. An N95 respirator should be doffed and discarded or stored after use on patients with suspected or confirmed COVID-19 and a clean mask or respirator should be donned before care of patients without COVID-19.

If an N95 is stored and reused, the CDC states reuse of N95 respirators should be limited to no more than five uses (ie, five donnings) per device by the same HCP, unless otherwise specified by the manufacturer [19]. There is some concern that respirators may not provide sufficient protection with repeated use. In one study of 68 HCP, approximately one-third failed a fit test that was performed using respirators worn for various durations; duckbill masks were more likely to fail compared with dome-shaped masks (71 versus 28 percent) [53]. However, the impact of these findings on transmission is unknown. There are no data to suggest a medical mask worn over an N95 provides additional respiratory protection, and the WHO discourages this practice [52].

Although extended use and limited reuse of PPE have been adopted in many health care settings, the WHO expresses concern about the potential for transmission of drug-resistant pathogens from reuse of PPE, including respirators and face masks [52]. In one report, extended use and reuse of PPE was likely associated with a nosocomial outbreak of a multidrug-resistant organism during the COVID-19 pandemic [14].

To help reduce the risk of transmission of multidrug-resistant organisms, the Infectious Diseases Society of America recommends a medical mask or face shield be worn over an N95 during aerosol-generating procedures to minimize contamination of N95s [43]. The use of a full-face shield also prevents HCP from having to change their mask or respirator after caring for patients who require contact or droplet precautions for other pathogens. On COVID-19 wards, where gowns are often used to care for several patients, gowns should be changed if a patient requires contact or droplet precautions for other drug-resistant organisms.

More detailed information on extended use and reuse of medical masks and N95 respirators can be found on the CDC and WHO websites [17,19,51,52].

Decontamination of PPE for reuse — Decontamination of personal protective equipment (PPE) for reuse, such as select face shields and N95 respirators, has been done in many medical centers during the COVID-19 pandemic when supplies have been critically low (crisis standards) [54,55]. In April 2021, The US Food and Drug Administration (FDA) announced there is a sufficient supply of respirators in the United States to transition away from the use of decontaminated disposable respirators [56].

If strategies are needed to conserve supplies of PPE in the setting of severe shortages, the CDC and WHO have highlighted several methods for decontamination of respirators [52,57]. These include:

Ultraviolet light – Decontamination with ultraviolet (UV) light was evaluated in the context of the H1N1 influenza pandemic; in experimental models, UV irradiation was observed to reduce H1N1 influenza viability on N95 respirator surfaces at doses below the threshold observed to impair the integrity of the respirator [58-60]. Coronaviruses can also be inactivated by UV irradiation, but comparable studies have not been performed with SARS-CoV-2, and the dose needed to inactivate the virus on a respirator surface is unknown. Nebraska Medicine has implemented a protocol for UV irradiation of N95 respirators in the context of the COVID-19 pandemic based on the dose generally needed to inactivate other single-stranded RNA viruses on surfaces [61].

Hydrogen peroxide vapor – Hydrogen peroxide vapor has been observed to inactivate other noncoronavirus single-stranded RNA viruses on environmental surfaces [62,63]. In one report, there were no effects on filtration efficiency or quantitative fit testing when N95 respirators were decontaminated with 59% vaporized hydrogen peroxide [64]. In the United States, The FDA granted an emergency use authorization for use of low-temperature vaporous hydrogen peroxide sterilizers, used for medical instruments, to decontaminate N95 respirators [57,65].

Moist heat – Moist heat has been observed to reduce the concentration of H1N1 influenza virus on N95 respirator surfaces [59]. In this study, moist heat was applied by preparing a container with 1 L of tap water in the bottom and a dry horizontal rack above the water; the container was sealed and warmed in an oven to 65°C/150°F for at least three hours; it was then opened, the respirator placed on the rack, and the container resealed and placed back in the oven for an additional 30 minutes. No residual H1N1 infectivity was found. The optimal time and temperature to inactivate SARS-CoV-2 are uncertain; several studies observed inactivation of SARS-CoV after 30 to 60 minutes at 60°C/140°F [66-68].

If decontamination of PPE is done, staff should be cautioned to not wear makeup, use lotions or beard oils, or write on masks, as they make decontamination difficult or impossible. The National Personal Protective Technology Laboratory developed a list of products assessed using various decontamination strategies [69].

In a systematic review of N95 respirator reprocessing that included 42 laboratory-based studies, UV germicidal irradiation, vaporized hydrogen peroxide, moist heat, and microwave-generated steam processing effectively sterilized many different pathogens on N95s and retained filtration performance (although UV irradiation and vaporized hydrogen peroxide damaged respirators the least) [70]; however, studies specifically evaluating SARS-CoV-2 were limited.

Environmental disinfection — To help reduce the spread of COVID-19, environmental infection prevention procedures should be implemented [11,12,71-73]. In United States health care settings, the CDC states routine cleaning and disinfection procedures are appropriate for SARS-CoV-2 [11]. Products approved by the EPA for emerging viral pathogens should be used; a list of EPA-registered products can be found here. Specific guidance on environmental measures, including those used in the home setting, is available on the CDC and WHO websites.

Vacant rooms recently occupied by patients with SARS-CoV-2 infection or in which an aerosol generating procedure has been performed should be left empty as long as possible before cleaning, to allow air turnover [11]. (See 'Aerosol-generating procedures/treatments' above.)

Many hospitals have implemented enhanced environmental cleaning and disinfection protocols for rooms used by patients with known or suspected COVID-19 and for areas used by HCP caring for such patients to prevent secondary transmission from fomites. As an example, adjunctive disinfection methods, such as UV light and hydrogen peroxide vapor, are used in some facilities to disinfect the rooms that have housed or been used for aerosol-generating procedures on patients with COVID-19. The use of upper-room germicidal UV (GUV) fixtures has also been proposed [74]; these fixtures contain bulbs that produce UV-C irradiance that has higher energy than normal sunlight. Although GUV fixtures have been used to reduce airborne transmission of pathogens such as tuberculosis [74,75], the clinical utility of GUV for reducing transmission of SARS-CoV-2 is unknown. There are also safety concerns, since GUV light fixtures can produce sunburn-like skin reactions and eye damage as well as generate ozone if strict safety measures are not utilized in their installation and maintenance [76].

Environmental services workers who are cleaning and disinfecting areas potentially contaminated with SARS-CoV-2 should be trained to conduct the cleaning and disinfection in appropriate PPE. The specific approach to PPE depends upon the institution. In general, environmental services workers can use droplet and contact precautions, plus eye protection (surgical mask, face shield or goggles, gown, and gloves) when cleaning and disinfecting areas used by HCP who are caring for patients with COVID-19. Workers should also be fit tested and trained to wear N95 respirators and face shields (or PAPRs) for cleaning and disinfecting patient rooms that are or have been occupied by persons with known or suspected COVID-19 or have been used for aerosol-generating procedures on patients with COVID-19.

The role of environmental disinfection was illustrated in a study from Singapore, in which viral RNA was detected on nearly all surfaces tested (handles, light switches, bed and handrails, interior doors and windows, toilet bowl, sink basin) in the airborne infection isolation room of a patient with symptomatic mild COVID-19 prior to routine cleaning [77]. Viral RNA was not detected on similar surfaces in the rooms of two other symptomatic patients following routine cleaning (with sodium dichloroisocyanurate). Of note, viral RNA detection does not necessarily indicate the presence of infectious virus. The role of environmental contamination in transmission of SARS-CoV-2 is discussed elsewhere. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Environmental contamination'.)

INFECTION PREVENTION IN THE HOME SETTING — Home management is appropriate for patients with mild infection who can be adequately isolated in the outpatient setting [71,78,79]. (See "COVID-19: Outpatient evaluation and management of acute illness in adults" and "COVID-19: Management in hospitalized adults".)

Management of such patients should include instructions on how to prevent transmission to others.

Isolation at home — Outpatients with suspected or confirmed COVID-19 (including those awaiting test results) should stay at home and try to separate themselves from other people and animals in the household [80,81]. They should also avoid having visitors enter the home.

Patients should wear a face mask for source control if they must be in the same room (or vehicle) as other people. Detailed information on the use of masks for patients can be found on the CDC website [82]. The WHO has also issued standards for the ideal composition of a cloth mask to optimize fluid resistance and filtration efficiency [15]. Masks with exhalation valves or vents should be avoided since they do not provide source control.

Caregivers and those sharing a living space with individuals with known or suspected COVID-19 should also wear a mask when in the same room (or vehicle) as the patient [15,83]. When medical masks are not available, household contacts should use a nonmedical mask (eg, cloth mask). Emerging evidence suggests cloth masks appear to provide some protection to the wearer [84], and the combination of the patient and caregiver wearing a mask may be synergistic [85,86]. An experimental study by the CDC suggests even greater protection to the wearer from adjusting the fit of a surgical mask or wearing a cloth mask over a surgical mask [27]. (See "COVID-19: General approach to infection prevention in the health care setting", section on 'Universal use of masks'.)

In many settings, multiple members of the same household will acquire COVID-19 from one another. When this occurs, household contacts with COVID-19 do not need to isolate from each other.

Other measures — Other steps to reduce transmission in the home include [15,71,83,87,88]:

Limiting the number of caregivers and, if possible, using caregivers who are fully vaccinated and do not have risk factors for developing severe disease. (See "COVID-19: Clinical features", section on 'Risk factors for severe illness'.)

Having patients use a separate bedroom and bathroom, if available.

Minimizing patients' exposure to shared spaces and ensuring shared spaces in the home have good air flow, such as an air conditioner or an opened window. When sharing spaces cannot be avoided, patients and caregivers should try to remain six feet (two meters) apart, if possible, and face masks should be used.

Ensuring caregivers perform hand hygiene after any type of contact with patients or their immediate environment. In addition, caregivers should wear gloves, if available, when touching the patient's blood, stool, or body fluids, such as saliva, sputum, nasal mucus, vomit, and urine.

Educating caregivers on how to carefully put on and take off personal protective equipment (PPE). As an example, caregivers should first remove and dispose of gloves and then immediately clean their hands with soap and water or alcohol-based hand sanitizer. After that, the mask should be removed, and the caregiver should again perform hand hygiene.

Instructing family members to avoid sharing dishes, drinking glasses, cups, eating utensils, towels, bedding, or other items with the patient. After the patient uses these items, they should be washed thoroughly; hand hygiene should be performed when handling these items. In addition, thermometers should not be shared, or should be thoroughly disinfected before use by other household members.

Avoid unmasked time together such as during eating or drinking.

Cleaning and disinfecting shared spaces and frequently touched surfaces [71,89]. When disinfection is also required, most common Environmental Protection Agency (EPA)-registered household disinfectants are thought to be effective. There is no evidence to support ultraviolet (UV) disinfection of personal items in the home setting. Detailed information on when and how to clean and disinfect can be found on the CDC website.

The above recommendations should be followed even if the caregiver had SARS-CoV-2 infection within the last 90 days or was fully vaccinated with one of the available COVID-19 vaccines. (See "COVID-19: Vaccines".)

For patients who require nebulizer treatments, certain precautions should be taken to reduce the risk of aerosol transmission to others. As an example, the nebulizer should be used in a location that avoids/minimizes exposure to other members of the household, and it should be used in a location where air is not recirculated into the home (eg, a porch, patio, or garage) [73]. For patients with sleep apnea, the use of a continuous positive airway pressure (CPAP) machine may also lead to aerosolization of virus, and the decision to use CPAP during infection must be determined on a case-by-case basis [90].

Behavioral interventions that stress the importance of infection prevention measures in the home and provide strategies to overcome barriers may enhance adherence to these precautions [91].

More detailed recommendations on home management of patients with COVID-19 can be found on the WHO and CDC websites [71,87].

DISCONTINUATION OF PRECAUTIONS — Nontest-based and test-based strategies can be used to inform when infection prevention precautions should be discontinued in patients with SARS-CoV-2 infection [11,92]. For most patients, a nontest-based strategy is preferred; however, the ultimate choice depends upon the patient population and the severity of disease. (See 'Immunocompromised patients with confirmed infection' below.)

Nontest-based strategies allow for discontinuation of precautions based on improvement in symptoms and/or specific time intervals, whereas test-based strategies typically require two negative reverse-transcription polymerase chain reaction (RT-PCR) tests for SARS-CoV-2 on sequential respiratory specimens collected ≥24 hours apart. A detailed discussion of diagnostic testing for SARS-CoV-2 is found in a separate topic review. (See "COVID-19: Diagnosis".)

If patients are ready to be discharged home prior to meeting criteria for discontinuation of precautions, they can be sent home with instructions to self-isolate until they meet criteria. (See 'Symptom- and time-based strategies' below and 'Test-based strategies' below.)

Once infection prevention precautions/home isolation are discontinued, patients should still continue to follow public health recommendations for wearing masks. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Personal preventive measures'.)

Immunocompetent patients with confirmed infection — For most immunocompetent patients with COVID-19, a nontest-based strategy should be used to determine when precautions can be discontinued. This approach is supported by both the United States Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) [92,93]. (See 'Symptom- and time-based strategies' below.)

Test-based strategies are used infrequently in immunocompetent patients. Some patients have persistently positive polymerase chain reaction (PCR) testing for SARS-CoV-2 for weeks to months after resolution of symptoms, and this can unnecessarily prolong the need for infection prevention precautions and isolation since prolonged viral RNA shedding after symptom resolution is not clearly associated with prolonged infectiousness. (See 'Test-based strategies' below.)

As our knowledge of SARS-CoV-2 transmission continues to evolve, so do guidelines for isolation of patients with COVID-19. In immunocompetent persons, the approach to discontinuing isolation depends upon the severity of disease, the specific setting, and the need to maintain a critical work force. This section will review guidelines put forth by the CDC. However, local public health guidelines and institutional policies may vary.

In the health care setting — The approach to discontinuing isolation in the health care setting differs from that in the general community. Hospitalized patients include certain groups (eg, older or highly immunocompromised patients) who are at increased risk for severe disease, and guidelines used in the community recommending shorter periods of isolation but masking at all times when around others may not be feasible and could put patients and staff at increased risk of infection.

Symptom- and time-based strategies — Nontest-based strategies in immunocompetent patients depend upon the severity of disease. Available evidence suggests that transmission most likely occurs during the early stage of infection and that isolation of infectious virus more than 10 days after illness onset is rare in immunocompetent patients who have improved after nonsevere infection [92]. Recovery of replication-competent virus for longer periods of time after symptom onset has been occasionally described, mainly in patients with severe disease or in those who have severe immunocompromise. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Viral shedding and period of infectiousness'.)

Nonsevere disease — For immunocompetent patients with nonsevere disease, the decision to discontinue precautions in the health care setting depends upon the presence of symptoms.

Mild to moderate disease – For patients with mild to moderate disease (eg, signs and symptoms of COVID-19 without hypoxia [oxygen saturation ≥94 percent on room air]), the CDC states that infection prevention precautions specific for COVID-19 home isolation can be discontinued when the following criteria are met [92]:

-At least 10 days have passed since symptoms first appeared; and

-At least one day (24 hours) has passed since resolution of fever without the use of fever-reducing medications; and

-There is improvement in symptoms (eg, cough, shortness of breath).

The WHO endorses the use of similar nontest-based strategies to end precautions/isolation [93], but for symptomatic patients, they suggest patients be without fever or respiratory symptoms for at least three days [93].

Some institutions have modified these guidelines to simplify the decision-making process. As an example, at Duke University, infection control precautions for COVID-19 are discontinued 10 days after the first positive test in immunocompetent patients with nonsevere disease (regardless of when symptoms occur); although this approach may extend the duration of isolation, it avoids confusion about defining the exact date of symptom onset. Information on other institutional protocols is found elsewhere. (See "COVID-19: Management in hospitalized adults", section on 'Institutional protocols'.)

Asymptomatic patients – Some patients have laboratory-confirmed SARS-CoV-2 infection without any symptoms. For such patients, infection prevention precautions specific for COVID-19 home isolation can be discontinued when at least 10 days have passed since the date of their first positive COVID-19 test, as long as there was no evidence of subsequent illness. If symptoms developed, the symptom-based strategy should be used.

Severe or critical disease — The duration of isolation is extended for patients with severe or critical illness (eg, oxygen saturation <94 percent on room air, need for oxygenation or ventilatory support) since they may shed virus longer than those with more mild disease [92,94]. Such patients can typically discontinue infection prevention precautions specific for COVID-19 when the following criteria are met [92]:

At least 10 and up to 20 days have passed since symptoms first appeared; and

At least one day (24 hours) has passed since resolution of fever without the use of fever-reducing medications; and

There is improvement in symptoms (eg, cough, shortness of breath).

The decision to discontinue precautions within this 10- to 20-day time frame should be individualized. A test-based strategy may be helpful to inform the duration of isolation. (See 'Test-based strategies' below.)

If a test-based strategy is not feasible, the duration of isolation should be made in consultation with infection prevention, infectious diseases, or public health experts.

Test-based strategies — If a test-based strategy is used, symptomatic patients may discontinue infection prevention precautions specific for COVID-19 when there is [92]:

Resolution of fever without the use of fever-reducing medications; and

Improvement in symptoms (eg, cough, shortness of breath); and

Negative results of a viral assay for SARS-CoV-2 from at least two consecutive respiratory specimens collected ≥24 hours apart (total of two negative specimens). In the United States, this should be a US Food and Drug Administration (FDA) emergency use-authorized test.

Patients with SARS-CoV-2 infection who are asymptomatic also require negative results of a viral assay from at least two consecutive respiratory specimens collected ≥24 hours apart (total of two negative specimens).

The CDC states an antigen or nucleic acid amplification test (NAAT; eg, reverse-transcription polymerase chain reaction [RT-PCR]) can be used for a test-based strategy [95]. However, we prefer NAATs when testing is performed in health care settings since it is more sensitive than antigen testing and, as a result, may further reduce the risk of SARS-CoV-2 transmission to other patients who may be at high risk for severe disease should they develop COVID-19. (See "COVID-19: Diagnosis", section on 'Specific diagnostic techniques'.)

There is no clear guidance as to when repeat testing should be performed. The timing depends in part upon why a test-based strategy is being used. However, if the first test is positive, we wait 72 hours before obtaining a second test. Once the first test is negative, the second test should be obtained 24 hours later. Additional information on the use of test-based strategies in immunocompromised patients is discussed below. (See 'Immunocompromised patients with confirmed infection' below.)

When a test-based strategy is used, some patients may have persistently positive PCR testing for SARS-CoV-2 for weeks to months after resolution of symptoms. This can pose unresolved questions in the health care setting since concerns that the patient could still be infectious may result in continued infection prevention precautions and possible further delay of important elective procedures or tests. In addition, prolonged isolation may have several negative consequences, including increased resource utilization (eg, PPE, tests, bed space on COVID-19 wards), decreased visits from providers to conserve PPE, prolonged visitor restrictions, and negative psychological effects [96].

There is no standardized approach for patients who persistently test positive, since viral culture, the gold standard for determining infectivity, is not routinely available. However, available data suggest that prolonged viral RNA shedding after symptom resolution is not clearly associated with prolonged infectiousness in immunocompetent patients with mild to moderate disease. This is why symptom- and time-based approaches for discontinuing precautions are typically recommended for these patients, as described above. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Viral shedding and period of infectiousness' and 'Symptom- and time-based strategies' above.)

If a test-based strategy was used and the person continues to test positive, some clinicians have used the cycle threshold (Ct) to help assess infectivity; the higher the Ct, the fewer the RNA copies. However, the Ct should generally not be used to determine when a person can be released from isolation [97]; Ct values are not standardized across RT-PCR platforms, Ct values can be affected by factors other than viral load (how the specimen was stored), and no clinical studies have validated use of Ct to guide management. (See "COVID-19: Diagnosis", section on 'Cycle threshold'.)

There has also been some interest in whether development of antibody correlates with disease activity, but similar to the Ct, there are insufficient data to use this information to guide clinical decisions. (See "COVID-19: Diagnosis", section on 'Serology to identify prior/late infection'.)

In the community setting — In December 2021, the United States CDC shortened the recommended duration of isolation for certain immunocompetent patients with SARS-CoV-2 in the general community since available evidence demonstrates most transmission occurs during the early periods of infection [95,98,99]. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Transmission'.)

Initial five days – All symptomatic patients with SARS-CoV-2 infection should isolate for the first five days after symptoms develop (ie, day 1 through day 5 after symptom onset, with day 0 being the first day of symptoms). Asymptomatic persons should also isolate through day 5, with day 0 being the date the specimen was collected for the positive viral test. (See 'Isolation at home' above.)

Who can end isolation after five days – After five full days (ie, day 6), certain patients can leave home isolation. These include patients who are asymptomatic (assuming no subsequent illness develops) and those with mild disease who have been afebrile for 24 hours and whose symptoms are resolving. If repeat testing is performed toward the end of the five-day isolation period, a viral test (ideally an antigen test) should be negative.

All patients leaving isolation (even those with a negative viral test) should adhere to the following precautions for the next five days:

Wear a well-fitting mask around others at home and in public.

Avoid people who are immunocompromised or at high risk for severe disease, as well as health care and nursing home settings.

These precautions are required since there is still a small risk of transmission. Additional restrictions (eg, those related to travel) are found on the CDC website.

The need for continued masking through day 10 of illness, particularly among individuals with ongoing symptoms, those who are unvaccinated, and those who have not had prior COVID infection, was supported in a report of 729 patients who were diagnosed with SARS-CoV-2 infection from January to February of 2022 [100]. In this study, approximately 54 percent of patients had a positive antigen test result five to nine days after symptom onset or, in asymptomatic persons, after the first positive test. An antigen test was more likely to be positive after five than after nine days (adjusted odds ratio [aOR] 6.39; 95% CI 3.39-12.03) and was more likely to be positive in those with symptomatic infection (aOR 9.63; 95% CI 6.03-15.37). By contrast, the antigen test was less likely to be positive in those with previous infection (aOR 0.30; 95% CI 0.19-0.46), those who received a primary COVID-19 vaccination series (aOR 0.60; 95% CI 0.39-0.93), and those who had both previous infection and received a primary COVID-19 vaccination series (aOR 0.17; 95% CI 0.09-0.33).

Who should continue isolation for ≥10 days – Persons who continue to have fevers or whose symptoms have not improved after five days of isolation, those with a positive viral test performed around day 5, and those who are unable to wear a mask around others should continue to isolate at home for the full 10 days.

Those with moderate or severe disease should also isolate for ≥10 days. For patients with severe disease, the duration of isolation may need to be extended up to 20 days, as discussed above. (See 'Symptom- and time-based strategies' above.)

The CDC has developed a calculator to help clarify the duration of isolation. This can be found on the CDC website.

Return to work for health care personnel — Return to work criteria for health care personnel (HCP) differ from the approach to ending isolation for patients in the hospital setting and in the community. This is discussed in detail elsewhere. (See "COVID-19: Occupational health issues for health care personnel", section on 'Return to work criteria'.)

"Rebound" infection after nirmatrelvir-ritonavir treatment — Some individuals with COVID-19 will receive nirmatrelvir-ritonavir to reduce the risk of hospitalization.

However, there are reports of patients experiencing return of antigen-positivity on rapid testing, with or without recrudescent symptoms, several days after completion of the five-day course of treatment.

When this occurs, patients in the community setting should isolate again for five days (day 0 is onset of symptom recurrence or a new positive test result) and then continue to mask around others for another five days [101]. (See 'In the community setting' above.)

Patients with rebound infection in the hospital setting should isolate as well. (See 'In the health care setting' above.)

Immunocompromised patients with confirmed infection — The approach to discontinuing precautions in immunocompromised patients depends upon the degree of immunocompromise.

Patients who are moderately to severely immunocompromised – For those with moderate to severe immunocompromise (table 1), the CDC suggests the duration of isolation be determined using a test-based strategy since such patients can shed viable virus for prolonged periods of time, regardless of disease severity [92,95,102]. This same approach should be used for those who are asymptomatic. Test-based strategies are described above. (See 'Test-based strategies' above.)

In general, repeat testing should be performed at least 20 days after the onset of symptoms or after a positive viral test. If a patient has persistently positive NAATs beyond 30 days, additional testing may be warranted (eg, genomic sequencing or viral culture, cycle threshold). Such patients should be managed in consultation with an infectious diseases specialist.

Several reports have described viral shedding past the recommended 20-day isolation period in patients with a variety of different conditions that resulted in moderate to severe immunocompromise [102-111]. Viable SARS-CoV-2 was isolated in cell culture on days 25, 26, and 61 after symptom onset in 3 of 20 patients who had received a hematopoietic stem cell transplant, CAR-T cell therapy, or had lymphoma [102]. In another report, a patient with chronic lymphocytic leukemia and acquired hypogammaglobulinemia shed viable SARS-CoV-2 for 70 days [104]. Ongoing SARS-CoV-2 replication for 119 days was demonstrated in a patient with refractory mantle cell lymphoma and associated B cell immunodeficiency; in this patient, two episodes of clinical recrudescence of infection after the index hospitalization were also described [103]. In another patient with B cell depletion, viral shedding lasted a year; in this patient unique viral mutations developed [112].

Previously, the CDC considered a nontest-based strategy with a prolonged period of isolation to be a reasonable option for certain moderately to severely immunocompromised patients. However, it now favors a test-based strategy since guidelines are unable to encompass the range of timing in which immunocompromised patients can bring the virus under control.

Patients WITHOUT moderate to severe immunocompromise – In patients who are not moderately to severely immunocompromised, a time- or symptom-based strategy can be used to discontinue isolation, as described in the table (table 2).

Additional information on SARS-CoV-2 infection in immunocompromised patients is presented elsewhere.(See "COVID-19: Considerations in patients with cancer" and "COVID-19: Care of adult patients with systemic rheumatic disease" and "COVID-19: Issues related to solid organ transplantation".)

Suspected cases with negative initial testing — In some patients, initial testing is negative but there is still suspicion for COVID-19. In this setting, a second test should be performed and infection prevention precautions should be continued pending the result. False-negative NAATs (eg, RT-PCR) from upper respiratory specimens with positive tests from lower respiratory specimens have been well documented. (See "COVID-19: Diagnosis", section on 'Accuracy'.)

When two tests are negative, precautions for COVID-19 can often be discontinued; however, if concern for COVID-19 remains high (eg, a patient with consistent clinical symptoms and an exposure to a person with known or suspected COVID-19) and there is no alternative diagnosis, infection prevention precautions should be continued at least until criteria for discontinuation of precautions using a symptom-based strategy are met (table 2). Such patients should be managed in conjunction with an infectious diseases specialist, if possible, to help evaluate for alternative etiologies.

Suspected cases when testing was not performed — In some cases, testing for COVID-19 may not be accessible, particularly for individuals who have a compatible but mild illness that does not warrant hospitalization. In areas where community transmission of SARS-CoV-2 is widespread, these patients are often treated presumptively for COVID-19 (eg, home isolation, supportive care), and the decision to discontinue transmission-based precautions should be made using the symptom-based strategy described above.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: COVID-19 – Index of guideline topics".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

Basics topics (see "Patient education: COVID-19 overview (The Basics)" and "Patient education: COVID-19 and pregnancy (The Basics)" and "Patient education: COVID-19 and children (The Basics)" and "Patient education: COVID-19 vaccines (The Basics)" and "Patient education: Recovery after COVID-19 (The Basics)")

SUMMARY AND RECOMMENDATIONS

General approach – Limiting transmission of SARS-CoV-2 is an essential component of care in patients with suspected or documented COVID-19. This includes universal source control (eg, covering the nose and mouth to contain respiratory secretions), early identification and isolation of patients with suspected disease, use of appropriate personal protective equipment (PPE) when caring for patients with COVID-19, and environmental disinfection. (See "COVID-19: General approach to infection prevention in the health care setting" and 'Infection prevention in the health care setting' above and 'Infection prevention in the home setting' above.)

Precautions in the health care setting – Person-to-person spread of SARS-CoV-2 is thought to occur via respiratory droplets as well as by smaller particles that remain airborne for longer and travel farther than usual respiratory droplets. Thus, the following infection prevention precautions should be used when caring for those with suspected or confirmed COVID-19 (see 'General approach' above):

Patients should be placed in a well-ventilated single-occupancy room with a closed door and dedicated bathroom; however, when this is not possible, patients with confirmed COVID-19 can be housed together. An airborne infection isolation room (ie, a single-patient negative-pressure room, direct out-exhausted air, >6 to 12 air exchanges) should be prioritized for patients undergoing aerosol-generating procedures. (See 'Type of room' above and 'Aerosol-generating procedures/treatments' above.)

All health care personnel (HCP) who enter the room of a patient with suspected or confirmed COVID-19 should wear PPE to reduce the risk of exposure. This includes the use of a gown, gloves, a respirator or medical mask, and eye or face protection. A respirator (eg, N95 or higher level of protection) should be used for all aerosol-generating procedures. We also suggest a respirator rather than a medical mask when providing routine care for patients with suspected or confirmed COVID-19 (Grade 2C). When PPE is severely limited, medical masks are an alternative for nonaerosol-generating procedures. Cautious extended or limited reuse of PPE can also be implemented in select situations. (See 'Type of PPE' above and 'When PPE is limited' above.)

The same infection prevention policies and precautions should be used for staff and patients, regardless of vaccination status. (See 'General approach' above and 'Type of PPE' above.)

Home isolation – Outpatients with suspected or confirmed COVID-19 (including those awaiting test results) who do not require hospitalization should stay at home and separate themselves from other people and animals in the household. Other strategies to help prevent transmission within the household include the use of masks and the cleaning of shared/frequently touched surfaces. (See 'Infection prevention in the home setting' above.)

Environmental disinfection – To help reduce the spread of COVID-19, environmental infection prevention procedures should be implemented in both health care and home settings. When disinfection is required, products approved by the Environmental Protection Agency (EPA) for emerging viral pathogens should be used; a list of EPA-registered products can be found here. (See 'Environmental disinfection' above and 'Other measures' above.)

Discontinuing precautions – For most patients, a time- or symptom-based strategy can be used to inform when infection prevention precautions should be discontinued in patients with SARS-CoV-2 infection; the specific criteria depend upon the severity of disease, the clinical setting (eg, community or health care setting), and the presence of certain underlying conditions (table 2). However, for those with moderate or severe immunocompromise, a test-based strategy is preferred since such patients may shed virus for prolonged periods of time. (See 'Discontinuation of precautions' above.)

If patients are ready to be discharged home prior to meeting criteria for discontinuation of precautions, they can be sent home with instructions to self-isolate until criteria are met. Once infection prevention precautions/home isolation are discontinued, patients should still continue to follow public health recommendations for wearing masks in public settings. (See 'Discontinuation of precautions' above.)

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