COVID-19: Occupational health issues for health care personnel

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); previously, it was referred to as 2019-nCoV.

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 (CDC) [1,2]. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Society guideline links'.)

This topic will provide information on prevention of COVID-19 in health care personnel (HCP) as well as management of HCP who have been exposed to or who have developed SARS-CoV-2 infection. Detailed discussions of the epidemiology and management of COVID-19 as well as the use of infection control precautions in health care settings are discussed in separate topic reviews. (See "COVID-19: Evaluation of adults with acute illness in the outpatient setting" and "COVID-19: Epidemiology, virology, and prevention" and "COVID-19: Management in hospitalized adults" and "COVID-19: Infection prevention for persons with SARS-CoV-2 infection" and "COVID-19: Management of adults with acute illness in the outpatient setting".)

EPIDEMIOLOGY — Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be transmitted when working in close proximity to coworkers, patients, clients, or customers. Studies show that the prevalence of COVID-19 is higher among people who work outside the home and in health care settings, suggesting that frequent contact with the public, customers, or patients may confer a higher risk of infection [3-7]. Globally, thousands of essential workers in diverse occupations have become infected or died from COVID-19. These include first responders, meat and poultry workers [8,9], retail clerks [10], transit operators [11], call center staff [12], shelter staff [13,14], corrections workers [15-18], warehouse workers, and health care personnel (HCP). The United States Centers for Disease Control and Prevention (CDC) considers an HCP to be any paid or unpaid person working in a health care setting who has the potential for exposure to patients and/or to infectious materials.

Information on the scope and magnitude of COVID-19 infections in HCP continues to evolve. Available data demonstrate the following:

●Burden of infection – According to data collected by the World Health Organization (WHO) prior to the availability of COVID-19 vaccines, 14 percent of COVID-19 cases reported to the WHO were among HCP [19]. In other reports, HCP have accounted for 3.8 to 19 percent of COVID-19 cases [20,21]. However, there is potential surveillance bias since HCP were tested at higher rates than the general population, particularly during the early months of the pandemic.

Several studies have evaluated the seroprevalence of infection in HCP, which appears to differ by region [22-25]. In one study from Germany, the seroprevalence of SARS-CoV-2 in 316 HCP was found to be 1.6 percent [22]; by contrast, in Belgium, the seroprevalence was 6.4 percent in a sample of 3056 HCP [23]. In both of these studies, many of those who tested positive endorsed prior symptoms, some of which were mild. However, in a survey of 20,614 HCP in the United States, in which 8.8 percent were seropositive, 44 percent reported they were asymptomatic during the month prior to serologic testing [24].

Several studies have also evaluated the severity of disease in HCP [26-32]. In many studies, HCP appear to have less severe illness compared with non-HCP [26-28], which may reflect the younger age of this population as well as detection of asymptomatic or milder disease with the use of broader testing in HCP, especially early on in the epidemic. HCP who require hospitalization or have fatal outcomes are more likely to have risk factors for severe disease [29-31]. In a report of 6760 adults hospitalized at 13 sites in the United States, 6 percent were HCP, and almost 90 percent had at least one underlying condition, obesity being the most common (73 percent) [31]. In a study from the United Kingdom, HCP and their households accounted for one in six of all COVID-19 admissions among those aged 18 to 65 years; the risk of admission was greatest in patient-facing HCP and their household members, as well as in older men with at least one comorbidity [30].

The risk of work-related infection among HCP has declined after the introduction of COVID-19 vaccination, with a greater proportion of HCP infections from community and household exposure. Breakthrough infections due to waning immunity and emergence of variants still present a risk to patients and coworkers, highlighting the need for ongoing screening and testing to prevent nosocomial transmission. (See 'Screening HCP' below.)

●Risk of acquiring infection in the health care setting – HCP are at risk of developing COVID-19 after unprotected exposures during patient care and nonpatient care activities. Data support the fact that appropriate infection control precautions, as well as the use of universal masking, can reduce this risk [24,26,33-36]. There are reports of infection despite using surgical masks and physical distancing, emphasizing the need for respiratory protection (eg, N95 and higher level respirators) [37,38]. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'General approach'.)

However, the exact risk of acquiring COVID-19 after an unprotected exposure to a patient in the health care setting is difficult to determine [20,21,39,40]. In an early report that described an outbreak in a long-term care facility, 50 HCP had confirmed COVID-19 that was linked to the facility [40]. However, another study found that only 3 of 121 HCP with an unprotected exposure to a patient with unrecognized COVID-19 were infected [41], and in a different report, no cases of COVID-19 developed in 11 HCP who had an unprotected exposure [42]. The differences in risk in different studies may be due to factors such as the type and duration of exposure and the stage of infection (early or late) in individual patients. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Viral shedding and period of infectiousness' and "COVID-19: Epidemiology, virology, and prevention", section on 'Risk of transmission depends on exposure type'.)

Many reports have found a higher proportion of COVID-19 cases among HCP in patient-facing roles [3,20,24,43,44], and in some reports, nurses appear to be at greatest risk [29,45]. HCP can also acquire infection in the community and bring it into the workplace, especially when community rates increase [21,23,36,46-53]. As an example, in a report that described 5374 high-risk exposures among HCP in Minnesota, approximately one-third were due to nonpatient contacts [51]. In a large seroprevalence study from Belgium, in which 6.4 percent of HCP had immune globulin (Ig)G antibodies for SARS-CoV-2, being directly involved in clinical care or working in a COVID-19 unit did not increase the odds of being seropositive, whereas having a household contact did [23].

●Impact of racial and ethnic disparities – Racial and ethnic disparities in COVID-19 infections may contribute to the burden of infection in various occupations in the United States, including HCP [54-63]. In the health care setting, racial and ethnic minorities may be at greater risk of acquiring COVID-19 since they are more likely to be employed in public-facing jobs, in which social distancing is not possible. As an example, African Americans make up 12 percent of all employed workers but account for 30 percent of licensed practical and licensed vocational nurses [64]. Similarly, Hispanic people represent 17.6 percent of the total employed population but make up 25 percent of the health care support workforce (which includes home health aides) [65].

Black and Latin American patients who develop infection are at increased risk for severe disease. In the United States, such patients account for a disproportionately high number of infections and deaths due to COVID-19, possibly related to underlying disparities in the social determinants of health [64,66]. In one study that described hospitalizations among HCP in the United States, approximately 60 percent were Black, Hispanic, or Latin American [31]. In another study, HCP with COVID-19 who died were more likely to be Asian or Black [29]. (See "COVID-19: Clinical features", section on 'Risk factors for severe illness'.)

In addition, there is also some evidence that air pollution, which disproportionately affects vulnerable communities, may contribute to COVID-19 severity [58,59,67,68].

●Risk of transmitting to patients – HCP have been associated with transmitting infection to patients, particularly in nursing home and long-term health care facilities [69-71]. Early in the pandemic a positive test in a nursing home worker prompted screening of residents, which found that 30 percent (23 of 76) tested positive [72]. Given this association, the CDC advises source control for all HCP and routine testing of unvaccinated HCP in nursing homes [73]. (See 'Testing for SARS-CoV-2' below and "COVID-19: Management in nursing homes".)

PREVENTING COVID-19 IN HEALTH CARE SETTINGS — Strategies to reduce the risk of acquiring COVID-19 in the health care setting include vaccination of health care personnel (HCP) and eligible patients; use of infection control precautions; routine use of face masks by all HCP, visitors, and patients; and screening for signs and symptoms of infection as well as possible exposures.

Vaccination

Indications — Vaccination with one of the available COVID-19 vaccines is indicated for all HCP, unless there is a contraindication (eg, allergic reactions to the vaccines or their components). In the United States, multiple medical societies support COVID-19 vaccination as a condition of employment for all HCP, unless they are exempt due to medical contraindications or subject to other exemptions as specified by federal or state law [74,75]. This includes nonemployees functioning at a health care facility (eg, students, contract workers, volunteers) [74].

In some countries, booster doses are now routinely recommended for those who previously completed their vaccine series. Although COVID-19 vaccination has markedly reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in HCP, cases can occur in fully vaccinated HCP. In one report, breakthrough infection in HCP who completed their initial vaccine series was correlated with lower neutralizing antibody titers during the peri-infection period [76].

More detailed information on the efficacy of COVID-19 vaccines, as well as information on vaccine administration, booster doses, contraindications, and precautions, is presented elsewhere. (See "COVID-19: Vaccines".)

Post-vaccination considerations — After vaccination, systemic signs and symptoms such as fever, fatigue, headache, chills, myalgia, and arthralgia can occur, and it can be challenging to distinguish these clinical manifestations from signs and symptoms of COVID-19 or other infectious diseases. (See "COVID-19: Vaccines", section on 'Expected adverse effects and their management'.)

The United States Centers for Disease Control and Prevention (CDC) has issued guidelines for management of HCP after vaccination [77]. Institutional policies may vary, but in general, HCP should be excluded from work pending further evaluation if they:

●Develop fever, fatigue, headache, chills, myalgia, and arthralgias and had a known unprotected exposure within the past 14 days

●Have a fever >100.0°F

●Have symptoms that are unlikely to be due to vaccination (eg, cough, shortness of breath, rhinorrhea, sore throat, loss of taste or smell).

Other HCP who develop systemic reactions that are typically observed following COVID-19 vaccination can continue to work but should be evaluated by employee health if the symptoms persist for more than 48 hours.

Use of infection control precautions — Transmission of SARS-CoV-2 occurs primarily through respiratory transmission via particles of different sizes [78-80]. Droplets are larger particles that can be propelled into the face (nose, mouth, and eyes). This type of transmission requires being relatively close (within 0.5 meters) to an infectious source. Transmission can also occur through smaller particles that can remain suspended in the air for long periods of time and can be inhaled by someone, usually in indoor environments [81-84]. Indirect (secondary) transmission, which occurs when a susceptible person touches a contaminated surface and then touches his or her eyes, nose, or mouth, is a less important route of transmission.

These modes of transmission inform the following infection control precautions when caring for a patient with confirmed or suspected COVID-19 in the health care setting:

●When entering the room of a patient with suspected or confirmed COVID-19, HCP should wear a gown and gloves, as well as personal protective equipment (PPE) that provides respiratory, eye, and face protection [85].

●For respiratory protection, we suggest a respirator (eg, N95 and higher level respirators) be used rather than a medical mask (eg, those commonly used during surgical procedures), since respirators provide both barrier and respiratory protection given their tight fit and filtration characteristics [86,87]. Although medical masks provide barrier protection against droplet sprays contacting mucous membranes of the nose and mouth, they are not designed to protect wearers from inhaling small particles. Respirators should be used as part of a respiratory protection program that provides staff with medical evaluations, training, and fit testing [88].

To optimize the supply of PPE during periods of shortage (eg, crisis capacity), reuse and extended use of N95 respirators have been implemented in many hospital settings [89]. In April 2021, The US Food and Drug Administration (FDA) announced there is an adequate supply of respirators in the United States to transition away from the use of decontaminated disposable respirators [90]. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'When PPE is limited'.)

●For eye or face protection, goggles or a face shield that cover the front and sides of the face should be used; glasses are not sufficient. If a powered air-purifying respirator [PAPR] is used, additional eye protection is not needed.

During the COVID-19 pandemic, enhanced infection control precautions (eg, face shields in addition to the universal use of masks or N95 respirators for all aerosol-generating procedures) should be used when caring for all patients, regardless of the individual suspicion for COVID-19. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection".)

More detailed information on the use infection control precautions is presented elsewhere. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection".)

Use of masks for source control — Health care facilities should implement policies that require HCP, patients, and visitors who enter the facility to wear a well-fitting face mask while in the building to provide source control [86]. Evidence supports the efficacy of masks to reduce viral transmission in the community and health care settings, especially to limit transmission during the asymptomatic or presymptomatic phase. More detailed discussions on the benefit of universal masking are presented elsewhere. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Wearing masks in the community' and "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Type of PPE' and "COVID-19: General approach to infection prevention in the health care setting", section on 'Universal use of masks'.)

Screening HCP — Health care personnel (HCP) should be routinely screened for evidence of symptoms and exposures. Screening should be used as an adjunct to an overall infection control program. (See 'Use of infection control precautions' above.)

Symptom and exposure screening — The approach to symptom and exposure screening varies depending upon the institution. We assess HCP daily; however, to make screening more feasible, some institutions require HCP to swipe their badge to acknowledge that they are without symptoms or exposures. When daily screening is not feasible, HCP should be educated about the need to report symptoms or exposures (both in the community and at work) to occupational health services.

We do not perform temperature checks for HCP prior to entry into the health care facility because it is not a sensitive tool to detect infection [91-93]. However, similar to symptom and exposure screening, institutional policies vary.

●Screening for symptoms – HCP should be questioned about the presence of any of the following symptoms that are new or unexplained by pre-existing conditions, both in the previous 24 hours and in the previous 10 days:

•Fever, chills, shivering/shakes (temperature >37.8°C/100°F)

•Cough

•Sore throat

•Runny or congested nose

•Difficulty breathing or shortness of breath

•Unexplained muscle aches

•Feeling unusually weak or fatigued

•Loss of sense of smell or taste

•Diarrhea (>3 loose stools in 24 hours)

•Eye redness with or without discharge ("pink eye")

Anyone who endorses these symptoms should be further evaluated and assessed via telephone interviews by occupational health personnel before resuming their regular work activities, unless the health care worker was previously evaluated by employee health for these symptoms and/or testing for COVID-19 was negative. A more detailed discussion of the approach to symptomatic HCP is found below. (See 'HCP with suspected or confirmed COVID-19' below.)

It is important to identify those with COVID-19 to help reduce transmission of virus to patients and staff in health care settings. In one report of 48 HCP with confirmed COVID-19 in Kings County, Washington, 65 percent reported working for a median of two days while exhibiting symptoms of COVID-19 [94]. In this study, more limited symptom screening (eg, fever, cough, shortness of breath, sore throat) would have missed 17 percent of symptomatic HCP [94]. In another report of 174 HCP with symptomatic COVID-19, about two-thirds reported fever or cough as an initial presenting symptom [95]. Policies that allow staff who are unwell to stay home without loss of income may encourage appropriate reporting of symptoms and prevent HCP from returning when infectious [19].

However, even expanded symptom screening may not identify all HCP with infection, since many HCP are either asymptomatic or presymptomatic [71,96-99]. Thus, universal use of masks by all staff, patients, and visitors is recommended in health care settings to limit transmission from asymptomatic persons. (See 'Use of masks for source control' above.)

●Exposure screening – We assess HCP for evidence of an exposure that may put them at increased risk of acquiring COVID-19 to determine the need for work restrictions. We ask if:

•In the past 30 days, has someone you lived with been diagnosed with COVID-19?

•In the past 10 days, have you been in unprotected close contact with someone diagnosed with COVID-19?

•In the past 10 days, have you returned from travel to a region requiring quarantine based upon local public health policies?

•In the past 10 days, have you worked at an outside facility and participated in direct patient care or had close contact with patients diagnosed with COVID-19?

If the health care worker answers yes to any of these questions, they should be evaluated by occupational health before resuming their regular work activities to determine the need for work restrictions. (See 'HCP exposed to SARS-CoV-2' below.)

Some institutions also assess for secondary contacts (eg, if you had contact with a person who had direct contact with a source patient, coworker, or household member). In these situations, quarantine is usually not needed, but HCP may be monitored by occupational health services.

Testing for SARS-CoV-2 — The approach to SARS-CoV-2 testing in HCP typically depends on whether testing is being performed for routine screening or for an outbreak investigation, and whether the worker is fully vaccinated (at least two weeks have passed after receiving the last dose in the vaccine series) [86]. In some countries, the approach to testing may also be determined by whether the HCP has received a booster dose of the vaccine.

For all other HCP, our recommendations are as follows:

●Routine screening – Routine screening with a viral test (eg, nucleic acid amplification testing [NAAT] or antigen testing) for SARS-CoV-2 in asymptomatic HCP is not performed in most health care settings [86]. However, testing is warranted for asymptomatic HCP who work in nursing homes and high-risk congregate living settings (eg, jails and prisons) if they are unvaccinated. There have been numerous outbreaks in these settings, and routine screening of asymptomatic HCP can be an important adjunct to symptom-based screening and outbreak testing [98,100-106].

The frequency of testing should be determined by local departments of public health and depends primarily upon the degree of community transmission [73,86,107]. As an example, in high-risk congregate settings located in counties with substantial to high community transmission, unvaccinated HCP should have a viral test twice per week. In areas with moderate community transmission, it is reasonable to screen unvaccinated HCP with a viral test once weekly. For those who work infrequently at these facilities, testing should be performed within 72 hours prior to the work shift, if possible.

A more detailed discussion of screening in HCP and residents in nursing homes is presented elsewhere. (See "COVID-19: Management in nursing homes", section on 'Routine screening and testing'.)

●Outbreak testing – Testing for SARS-CoV-2 with a viral test is indicated for HCP if there is an outbreak or a high-risk exposure, regardless of their vaccination status or the type of facility.

In the setting of an outbreak, initial testing should be performed in those who work in the affected units or department. Testing should occur as soon as possible (but not earlier than two days after the exposure), and if negative, again five to seven days after the exposure. If additional cases are identified, and contact tracing does not reduce transmission, more extensive testing may be warranted [73].

●Testing after an exposure - Information on testing after a known exposure to SARS-CoV-2 is discussed below. (See 'Determining the need for quarantine' below.)

There are no data to support the use of serologic testing to screen HCP for infection. Although serologic testing for SARS-CoV-2 may identify those who were asymptomatic and/or have recovered, a positive serologic test may not confer immunity or permit HCP to return to work without risk of subsequent infection [108,109]. (See "COVID-19: Diagnosis", section on 'Serology to identify prior/late infection'.)

HCP EXPOSED TO SARS-CoV-2

Initial evaluation — Health care personnel (HCP) should contact employee health as soon as possible if they think they had an exposure to a person (eg, patient, coworker, family member) with suspected or confirmed COVID-19 without using personal protective equipment (PPE). In the health care setting, appropriate PPE depends upon the type of interaction with the patient (eg, routine care versus an aerosol-generating procedure) and is discussed in detail elsewhere. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'General approach' and "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Approach in select settings'.)

We contact employees, usually within 12 hours, and obtain the following information to assess the exposure:

●If the health care worker completed a COVID-19 vaccine course and received a booster dose (if eligible).

●Whether the exposure occurred in the health care setting or at home.

●The proximity of the health care worker to the source patient. A proximity of six feet is typically used to determine if an exposure occurred for viral pathogens that are spread through respiratory droplets. Although there is some evidence that separations of three to six feet (one to two meters) may underestimate the distance needed for transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [110], this definition is reasonable until there are additional data assessing the risk of viral transmission during various patient care activities.

●The duration of the exposure (>15 minutes over a 24-hour period).

●The type of encounter (eg, was it in the context of an aerosol-generating procedure, was there unprotected direct contact with infectious secretions).

●The type of PPE the health care worker was wearing at the time of the encounter.

●The clinical symptoms of the source patient (eg, coughing likely increases exposure risk).

●Whether the patient was wearing a facemask.

Based upon this information we determine the need for work restrictions, as discussed below.

Assessing exposure risk — An exposure is considered to be high risk if:

●The health care worker was in the room during an aerosol-generating procedure and was not wearing all of the recommended PPE (gloves, gown, respirator, and eye protection).

●The health care worker had prolonged close contact (within six feet for ≥15 minutes over 24 hours) with a source patient during a nonaerosol-generating procedure and:

•The health care worker did not use respiratory protection (eg, respirator or medical mask), even if the source patient was wearing a facemask.

•The health care worker was not using a respirator (ie, using a medical mask or was unmasked) and the source patient was not wearing a facemask.

•The health care worker did not use eye protection and the source patient was not wearing a facemask.

All other exposures would be considered low risk.

Determining the need for quarantine — For HCP who have had a potential exposure to SARS-CoV-2, the United States Centers for Disease Control and Prevention (CDC) has provided guidelines for work restriction and monitoring [111]. The approach depends primarily upon whether the health care worker has completed the primary series of one of the available COVID-19 vaccines and received their booster shot if indicated. Other factors include the immune status of the worker, if there are staffing shortages, and if the exposure is considered high risk. (See 'Assessing exposure risk' above.)

The duration of quarantine is discussed below. (See 'Duration of quarantine' below.)

HCP who received all recommended COVID-19 vaccines — This section refers to HCP who completed their primary COVID vaccine series >2 weeks prior to their exposure and received their booster vaccine, if eligible. The recommended timing for booster vaccinations is discussed separately. (See "COVID-19: Vaccines", section on 'Dose and interval (for immunocompetent individuals)'.)

●Immunocompetent HCP – Immunocompetent HCP do not need to quarantine after an exposure in the hospital setting (including high-risk exposures) as long as they are asymptomatic, have completed their primary vaccine series at least two weeks prior to the exposure, and received their booster vaccine if eligible [111]. However, the CDC recommends testing with two viral tests for SARS-CoV-2, unless the health care worker recovered from SARS-CoV-2 infection within the previous 90 days. If testing is warranted, the first one should be performed as soon as possible (but not earlier than 24 hours after the exposure), and if negative, again five to seven days after the exposure. (See 'HCP with suspected or confirmed COVID-19' below.)

The approach to HCP who had a household exposure is less clear. Although guidelines do not recommend specific precautions for vaccinated HCP after an exposure to a household contact, some institutions recommend quarantine in this setting. The approach to quarantine in HCP who were exposed to a household contact differs from those exposed in the health care setting since there is a high risk of SARS-CoV-2 transmission among household contacts, and in vaccinated persons, there appears to be a higher rate of breakthrough infections with certain variants (eg, Omicron, the dominant variant in many countries). (See "COVID-19: Epidemiology, virology, and prevention", section on 'Risk of transmission depends on exposure type' and "COVID-19: Vaccines", section on 'Breakthrough infections after vaccination'.)

●Immunocompromised HCP – The approach to HCP who are immunocompromised must be determined on a case-by-case basis since some conditions may impact the response to COVID-19 vaccination and/or the risk of reinfection. More detailed information on COVID-19 vaccination in immunocompromised patients is presented elsewhere. (See "COVID-19: Vaccines", section on 'Immunocompromised individuals'.)

Recommended COVID-19 vaccines not completed — Some HCP may not have received all of the recommended COVID-19 vaccines. In the United States, this includes those who have not completed their primary vaccine series (or completed the primary vaccine series ≤2 weeks before their exposure), as well as those who have not received a booster shot if indicated. In this setting, indications for quarantine depends primarily upon concerns for staffing shortages and if the exposure is considered high or low risk. (See 'Assessing exposure risk' above.).

Preferred approach

●High-risk exposure in the health care setting – HCP who have not completed their recommended COVID-19 vaccines should generally quarantine after a high-risk unprotected exposure to a patient or coworker with suspected or confirmed SARS-CoV-2 infection. A source patient or coworker is considered infectious from two days before symptom onset or a positive test. The duration of quarantine is discussed below. (See 'Duration of quarantine' below.)

An exception to quarantine for HCP who have not completed their recommended COVID-19 vaccines may be asymptomatic HCP who had confirmed SARS-CoV-2 infection within the prior 90 days, since reinfection is unlikely during this period [111]. However, policies in individual institutions may vary and must take into account the health care worker’s underlying conditions (eg, are they immunocompromised) and the likelihood that they were exposed to a novel SARS-CoV-2 variant. (See "COVID-19: Epidemiology, virology, and prevention".)

●Low-risk exposure in the health care setting – Quarantine is not required for low-risk exposures in the health care setting. HCP with this type of exposure can continue working with universal masking and appropriate PPE but must self-monitor for the development of any symptoms.

●Exposure in the community – Unvaccinated HCP should quarantine if they were exposed to a household contact with suspected or confirmed COVID-19. The duration of quarantine is discussed below. (See 'Duration of quarantine' below.)

Considerable evidence suggests people exposed to household contacts are at greatest risk of acquiring infection with SARS-CoV-2 [112-114]. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Risk of transmission depends on exposure type'.)

For other exposures in the community, the need for quarantine must be determined based upon information obtained during the initial evaluation. (See 'Initial evaluation' above.)

When there are staffing shortages — When there are staffing shortages, the approach to quarantine after an exposure may differ for those who have not completed all of their recommended COVID-19 vaccines [115]. Decisions to use contingency strategies are dictated by local public health and hospital policy.

One strategy is to allow HCP without recent infection to continue working after a high-risk exposure, with the caveat that testing is required throughout the 14-day post-exposure period. In this setting, the United States CDC states that HCP should be tested one day after the exposure and, if negative, again two, three, and five to seven days after the exposure [115]. If testing supplies are limited, testing should be prioritized for one to two days after the exposure and, if negative, five to seven days after the exposure. More detailed information on alternative strategies to mitigate staffing shortages can be found on the CDC website.

If quarantine is not implemented due to staffing considerations, HCP should not work with immunocompromised or other high-risk patients (eg, patients with heart conditions or lung disease, pregnant patients). If the health care worker develops symptoms of COVID-19, they should self-isolate and contact occupational health. If symptoms develop while at work, HCP should leave immediately.

Duration of quarantine — Those who require quarantine should be excluded from work for 7 to 10 days. The duration depends in part upon the availability of testing.

●If testing is readily available, HCP can return to work after day 7 following the exposure if a viral (eg, antigen or nucleic acid amplification testing [NAAT]) test is negative for SARS-CoV-2 and HCP do not develop symptoms. The specimen for testing should be collected within 48 hours of the planned return to work.

●If testing is not performed, HCP can return to work 10 days following the exposure, as long as they do not develop symptoms. However, since there is a small residual risk of infection, some health care facilities may still require testing for SARS-CoV-2 within 48 hours before the HCP’s planned return.

Both of these approaches are shorter than the 14-day duration that had previously been recommended.

HCP should be monitored closely for symptoms through day 14 since there may be a small but increased risk of transmission through day 14 [116,117]. In addition, when workers return to work, masks should be used at all times in the hospital setting (except when eating) for source control. (See 'Use of masks for source control' above.)

HCP WITH SUSPECTED OR CONFIRMED COVID-19 — Our approach to management of health care personnel (HCP) with suspected or confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is the same for both vaccinated and unvaccinated HCP, as well as for HCP who had SARS-CoV-2 infection within the last 90 days. Although vaccination or prior infection reduces the chance of developing COVID-19, breakthrough infections occur [118]. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Risk of reinfection' and "COVID-19: Vaccines", section on 'Breakthrough infections after vaccination'.)

Initial approach

Symptomatic HCP — Health care personnel (HCP) who report any symptoms consistent with COVID-19 (table 1) should contact employee health and be sent home if at work. This holds true for both vaccinated and unvaccinated HCP. Employee health practitioners should take a detailed history and obtain information needed for contact tracing. (See 'Case contact investigation' below.)

If symptoms are present and COVID-19 seems possible after an initial assessment, testing should be done. We prefer nucleic acid amplification testing (NAAT) if available, but some institutions may use antigen testing instead. The interpretation of antigen testing in symptomatic patients is discussed separately. (See "COVID-19: Diagnosis", section on 'Antigen testing'.)

●If testing is positive, HCP should isolate and seek appropriate medical care [111]. Return to work criteria are discussed below. (See 'Return to work criteria' below.)

●If testing is negative and the health care worker’s symptoms have improved, they can return to work. Nonspecific symptoms such as cough, sore throat, and myalgias are common, and it is not unusual for HCP with these complaints to have a negative test for SARS-CoV-2 [119].

However, if symptoms persist or are worsening, we usually repeat testing after 48 hours. If repeat testing is negative and the clinical suspicion for COVID-19 remains high, return to work should continue to be delayed. Additional information on diagnosis of COVID-19 is presented elsewhere. (See "COVID-19: Diagnosis", section on 'Diagnostic approach'.)

Asymptomatic HCP — Some asymptomatic HCP will test positive for SARS-CoV-2 as part of contact tracing or routine screening. Such workers should isolate; return to work criteria are described below. (See 'Return to work criteria' below.)

Return to work criteria — In the United States, the Centers for Disease Control and Prevention (CDC) has issued return to work criteria based primarily upon the immune status of the HCP and the severity of disease [111].

Protocols in other countries and at specific institutions may vary [19]. In addition, these criteria may differ from those used in the community. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'In the community setting'.)

Immunocompetent HCP — Return to work criteria for HCP with who are immunocompetent depend upon the severity of disease [111]. If testing is used to determine return to work criteria, antigen testing is typically preferred since NAAT may be positive for an extended period of time.

●HCP with severe to critical illness can generally return to work when they meet all the following criteria:

•Time criteria – 20 days have passed since symptoms first appeared;

•Fever criteria – At least 24 hours have passed since last fever without the use of fever-reducing medications;

•Symptom criteria – Symptoms (eg, cough, shortness of breath) have improved.

For such patients, an alternative approach for determining the duration of isolation is to use a test-based strategy (resolution of fever without the use of fever-reducing medications and improvement in symptoms and results are negative from at least two consecutive respiratory specimens collected ≥24 hours apart using an antigen test or NAAT).

●HCP with mild to moderate symptoms can return to work when they meet all the following criteria:

•Time criteria – At least 10 days have passed since symptoms first appeared. This period can be reduced to seven days if testing performed on day 5 is negative. If day 5 testing is positive, HCP must remain out of work until day 10.

•Fever criteria – At least 24 hours have passed since last fever without the use of fever-reducing medications.

•Symptom criteria – Symptoms (eg, cough, shortness of breath) have improved.

●HCP with no symptoms throughout their infection can return to work when:

•At least seven days have passed since the date of their first positive viral test if a negative antigen or NAAT is obtained within 48 hours prior to returning to work;

OR

•10 days have passed since the date of their first positive viral test if testing is not performed or a test obtained at day 5 to 7 was positive for SARS-CoV-2.

When there are staffing shortages, the return to work criteria may need to be modified. As an example, return to work in five days may be reasonable for immunocompetent HCP who are asymptomatic or mildly symptomatic (as long as the symptoms are improving and the HCP has had no fevers for 24 hours) [115]. When this strategy is used, we prefer to confirm resolution of infection with a negative antigen test or NAAT. If the test is positive, we let HCP return to work after day 10 without additional testing. These decisions are dictated by local state and hospital policy. Other strategies to mitigate staffing shortages can be found on the CDC website.

Immunocompromised HCP — Return to work criteria for immunocompromised HCP depends upon their degree of immunocompromise.

●Moderate to severe immunocompromise – Moderately to severely immunocompromised HCP include those with: active use of chemotherapy for cancer or other immunosuppressive medications (eg, mycophenolate mofetil, rituximab, prednisone >20 mg/day for >14 days), hematologic malignancies, receipt of CAR-T-cell therapy or hematopoietic stem cell transplant (within two years of transplantation or taking immunosuppressive therapy), advanced or untreated HIV infection with CD4 cell count <200 cells/microL, or moderate or severe primary immunodeficiency disorder.

For such HCP, the duration of isolation is the same as for non-HCP since moderately to severely immunocompromised patients with SARS-CoV-2 infection may produce replication-competent virus for prolonged periods of time (eg, more than 20 days). The approach to discontinuing precautions in these patients is discussed elsewhere. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Immunocompromised patients with confirmed infection'.)

●Other immunocompromised HCP – Some HCP may have a condition that leads to a lower degree of immunocompromise than those listed above. For such health care workers, return to work criteria should be individualized based upon the specific condition. For some, using one of the time-based strategies described for immunocompetent HCP may be reasonable. (See 'Immunocompetent HCP' above.)

CASE CONTACT INVESTIGATION — When a health care worker is diagnosed with COVID-19, case contact tracing is performed to assess significant exposures to coworkers and patients within the 48 hours prior to a positive test or symptom onset [120,121]. (See 'Initial evaluation' above and 'HCP with suspected or confirmed COVID-19' above.)

In order to protect confidential medical information (eg, positive test status of the health care worker), human resources or nonoccupational department managers should not be responsible for or notify employees or patients of the worker’s name and positive test status. All information collected as part of contact tracing should be considered medical information and protected from disclosure.

CASE CLASSIFICATION AND REPORTING — When a health care worker is diagnosed with COVID-19, occupational health should attempt to determine if the source of infection was work related. This type of investigation is important to evaluate the efficacy of infection control policies; inform frontline health care personnel (HCP) of their ongoing risk of work-related infection and engage them in efforts to improve worker protection programs; and determine the need for workers compensation and regulatory reporting. In the United States, employers and health care providers should report work-related outbreaks of COVID-19 to their local or state public health department [122,123].

COVID-19 is a nationally notifiable condition in the United States [124]. The Council of State and Territorial Epidemiologists (CSTE) has provided guidance to help determine if the infection is work related. Information can be found on the CSTE website.

Once a case of COVID-19 is determined to be work related, each different county and state in the United States has specific reporting requirements. As an example, in the United States, the Occupational Safety and Health Administration (OSHA) has issued enforcement guidance for recording cases of coronavirus illness [125]. Employers of workers in the health care industry must make work-relatedness determinations and must record this illness on their OSHA log if the COVID-19 illness results in death, days away from work, restricted work or transfer to another job, medical treatment beyond first aid, or loss of consciousness.

ADDITIONAL CONSIDERATIONS

Work restriction for high-risk HCP — Certain health care personnel (HCP) may be at high risk for adverse outcomes related to COVID-19 and, therefore, may warrant additional work restrictions, particularly if they are not vaccinated.

Persons with chronic medical conditions — Older adults (age >65 years) and individuals with serious underlying medical conditions are at higher risk for severe illness from COVID-19 (table 2). (See "COVID-19: Clinical features", section on 'Risk factors for severe illness'.)

HCP with serious underlying medical conditions that put them at higher risk for severe illness from COVID-19 (table 2) should be told to notify occupational health services, and they should be assessed on a case-by-case basis to determine if they are at high risk for serious illness, hospitalization, and death should they become infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [126]. When feasible, we offer these HCP the opportunity to work in lower-risk areas in the health care setting where exposure to patients with COVID-19 and coworkers is minimized. Occupational health services should also review any legal considerations regarding obligations to accommodate employees with medical conditions.

This approach is reasonable for both vaccinated and unvaccinated HCP, since the risk of breakthrough infection with certain variants (eg, Omicron) is unclear, and immunocompromised patients appear to have a reduced response to COVID-19 vaccination. (See "COVID-19: Vaccines".)

Pregnant HCP — There is no uniform approach to work restrictions for pregnant HCP; however, available data suggest that symptomatic pregnant patients with COVID-19 are at increased risk of more severe illness compared with those who are not pregnant. (See "COVID-19: Overview of pregnancy issues".)

In general, pregnant HCP may continue to work in patient-facing roles until they give birth if all recommended personal protective equipment (PPE) is available [127], but it is reasonable to limit exposure to patients with confirmed or suspected COVID-19, particularly during higher-risk procedures (eg, aerosol-generating procedures) and/or if the health care worker is unvaccinated. Pregnant HCP should contact occupational health and be informed of the options for reassignment and/or work restrictions, especially as they are near term [128-132].

Reducing risk of transmission at home — Many HCP are concerned about transmitting SARS-CoV-2 to family members after working in the health care setting. The risk of vaccinated HCP transmitting infection to family members is probably minimal or small. However, there are no data to define this risk or to guide recommendations, and HCP have adopted a range of practices (eg, showering or changing clothes when they return home).

HCP who had a high-risk unprotected contact with a patient with COVID-19 and are required to isolate should isolate at home in a separate bedroom and use a separate bathroom if possible. When this is not possible, some institutions offer HCP alternate accommodations. Additional information on management of HCP exposed to COVID-19 is found above. (See 'HCP exposed to SARS-CoV-2' above.)

Mental health impact — Frontline HCP caring for patients with COVID-19 may experience a number of emotional and behavioral responses [133-135]. In one report, workplace factors, such as availability of PPE, staff training, and provision of mental health support, were associated with depressive symptoms during COVID-19 [136,137].

Distress responses to life-threatening circumstances are normal but can overwhelm coping capacities [138]. Acute responses can be categorized as emotional reactions (eg, fear, anxiety, guilt, sadness, irritability, or depression); physical symptoms (eg, palpitations, shortness of breath, sweating, loss of appetite, dizziness, or sleep impairment); disturbances of attention (eg, confusion, distractibility, or hyper-alertness); and behavioral changes (eg, increase in alcohol and drug use, cigarettes, aggressive/violent behavior, heroic activity which may lead to burnout, withdrawal, and disruption of normal routines) [139]. These emotional responses can aggravate underlying and pre-existing mental health disorders or precipitate new psychiatric conditions, such as depression, post-traumatic stress disorder, substance and alcohol use disorders, or relapse. The United States Centers for Disease Control and Prevention (CDC) and other organizations have provided guidance and resources to help HCP address these mental health challenges [140-144].

A more detailed discussion of the mental health impact of COVID-19 in HCP is discussed in a separate topic review. (See "COVID-19: Psychiatric illness".)

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 5^th to 6^th 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 10^th to 12^th 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)")

SUMMARY AND RECOMMENDATIONS

●Health care personnel (HCP) are at risk for acquiring COVID-19 by working in close proximity to patients and coworkers. Prior to the availability of the COVID-19 vaccine, reports found HCP accounted for 3.8 to 19 percent of COVID-19 cases. However, the exact risk of acquiring COVID-19 after an unprotected exposure to a patient in the health care setting has been difficult to determine and depends in part upon the type of exposure and when a patient is most infectious. (See 'Epidemiology' above.)

●Strategies to reduce the risk of acquiring COVID-19 in the health care setting include vaccination with one of the available COVID-19 vaccines; adherence to infection control precautions; mandatory use of face masks by all HCP, visitors, and patients; screening for signs and symptoms of infection; and in some settings, testing of asymptomatic HCP. (See 'Preventing COVID-19 in health care settings' above.)

●HCP who were exposed to a person (eg, patient, coworker, family member) with suspected or confirmed COVID-19 within the last 10 days without using personal protective equipment (PPE) should contact employee health to determine the need to quarantine. The need for and type of work restrictions depend upon HCP vaccination status and underlying conditions, the type of interaction with the patient (eg, routine care versus an aerosol-generating procedure), the type of PPE that was used, the duration of the exposure (eg, ≥15 minutes over 24 hours), the proximity to the patient (eg, within six feet), and the presence of staffing shortages. (See 'HCP exposed to SARS-CoV-2' above.)

●For HCP with symptoms of COVID-19, we arrange testing within the next 24 hours. If testing is negative and the symptoms are improving, they can go back to work. However, if symptoms persist or are worsening, we typically repeat testing 48 hour later. If repeat testing is negative and the clinical suspicion for COVID-19 remains high, return to work should still be delayed. (See 'HCP with suspected or confirmed COVID-19' above.)

●HCP with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can return to work after meeting criteria for discontinuing precautions using a nontest-based strategy based upon duration of time after onset of and resolution of symptoms (or time from a positive test for those without symptoms). However, in immunocompetent HCP with asymptomatic or mild to moderate disease, it is reasonable to shorten the duration (eg, from 10 days to five to seven days) if there are staffing shortages, particularly if testing is available. For immunocompromised HCP, the duration of quarantine depends upon the degree of immunocompromise. (See 'HCP with suspected or confirmed COVID-19' above.)

●Some HCP (eg, older individuals, those with comorbid conditions, pregnant patients), particularly those who are unvaccinated, may warrant work restrictions to reduce exposure to patients with COVID-19, since such HCP are at high risk for adverse outcomes if they become infected. (See 'Work restriction for high-risk HCP' above.)