Viral Respiratory Infections

Infection Control in Healthcare Personnel
For Health Care Providers
Healthcare Personnel: Part I

What to know

  • Guideline: Infection Control in Healthcare Personnel
  • Segment: Part II Epidemiology and Control of Selected Infections
  • Summary: Recommendations and resources for the management of healthcare personnel exposed to or infected with a viral respiratory infection.

Recommendations

  1. For asymptomatic healthcare personnel who have a known or suspected exposure to a respiratory virus not addressed elsewhere in this guideline or other interim guidance+:
    • Work restrictions are not necessary.
    • Wear source control from the day of first exposure through at least the 5th day after last exposure*.
    • Monitor for development of signs or symptoms of a viral respiratory infection for at least 5 days after their last exposure.
      • Healthcare personnel who develop signs or symptoms of a viral respiratory infection should be restricted from work as described in recommendation 2.
  1. For healthcare personnel with a suspected or confirmed viral respiratory infection not addressed elsewhere in this guideline or other interim guidance+:
    • Restrict from work until:
      • At least 3 days have passed from symptom onset** (or from their first positive respiratory virus test if asymptomatic throughout their infection), AND
      • They are fever free for at least 24 hours without the use of antipyretics, AND
      • Symptoms are improving, AND
      • They feel well enough to return to work.
    • Wear source control upon return to work until at least the end of day 7, where the day of symptom onset (or first positive test if asymptomatic throughout their infection) is day 0***.

+ This recommendation is intended to apply to respiratory viruses such as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), influenza, respiratory syncytial virus (RSV), parainfluenza, rhinovirus, human metapneumovirus, and additional adenoviruses, endemic coronaviruses, enteroviruses, and others. This recommendation is NOT intended to apply to viral respiratory pathogens addressed in other sections of this guideline (i.e., measles, mumps, rubella, varicella, cytomegalovirus, parvovirus B19, and viral conjunctivitis) or other interim guidance (e.g., Middle East Respiratory Syndrome coronavirus).

* Where the last day of exposure is day 0, making the first possible day of working without source control day 6.

** Where the day of symptom onset is day 0, making the first possible day of return to work on day 4.

*** Making the first possible day of working without source control day 8.

Background

Viral respiratory pathogens are a large and diverse group of pathogens that include viruses such as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), influenza viruses, respiratory syncytial virus (RSV), parainfluenza viruses, rhinoviruses, human metapneumovirus, additional adenoviruses, endemic coronaviruses, and enteroviruses.

Many viral respiratory pathogens have been reported to be transmitted between healthcare personnel (HCP) and patients in healthcare settings, such as SARS-CoV-2123, influenza viruses45, and RSV6. Although SARS-CoV-2, influenza viruses, and RSV are among epidemiologically important viral respiratory pathogens that can be transmitted in healthcare settings, other pathogens can be as well.

Respiratory virus transmission between HCP and patients/residents has been well described2, but transmission in healthcare settings can be complex and also involve transmission among HCP as well as anyone else present in a healthcare facility57. Many infections in HCP have been reported to be acquired in the community8.

Restricting infected HCP from work while contagious is a mainstay of infection prevention and control and one part of a hierarchy of controls9 used in healthcare settings for preventing transmission and maintaining a safe work and patient care environment1011. However, restricting HCP from work has the potential to cause harm, such as staffing shortages, which can result in lapses in HCP safety and suboptimal patient care12131415. Therefore, it is important to exclude HCP with viral respiratory infection(s) from work for long enough to mitigate risk of pathogen transmission while minimizing any unintended health and safety consequences for HCP and patients.

Preventing transmission of viral respiratory pathogens in healthcare settings involves (a) ensuring HCP are immunized against respiratory pathogens for which the Advisory Committee on Immunization Practices (ACIP) and CDC recommends vaccine for HCP; (b) using infection prevention and control practices as recommended by CDC16; (c) excluding potentially infectious HCP from work; and (d) using source control for the recommended duration for HCP who return to work. The recommendations for immunizing HCP against individual viral respiratory pathogens are maintained by CDC and ACIP.1718

Occupational exposures

The dynamics of respiratory virus transmission during a person's illness vary between pathogens. Reports on SARS-CoV-2 transmission indicate that asymptomatic, presymptomatic, and symptomatic transmission of the virus is possible; the risk of asymptomatic and presymptomatic transmission for other respiratory viruses is less clear but likely varies. Respiratory viruses can transmit to a susceptible host via several modes, including through the air and via touch.

Exposure to a respiratory virus can be generally defined as being within close proximity of an infectious source person (e.g., within a patient/resident room) while unprotected (i.e., not wearing recommended personal protective equipment) or having mucous membrane contact with their secretions (e.g., touching a contaminated surface and then touching one's eyes). Being closer to an infectious person likely carries a greater risk for transmission as it may expose HCP to a higher concentration of potentially infectious particles. The amount of exposure time used to consider HCP as 'exposed' is difficult to define and may vary between viral respiratory pathogens. For SARS-CoV-2, 15 minutes of contact over a 24-hour period was previously used to identify an exposure (and illustrate the minimal risk of a transient exposure), based upon reports of transmission in healthcare settings1. However, people exposed for less than 15 minutes could still develop SARS-CoV-2 infection in some circumstances. Ultimately, when determining exposures among HCP, Occupational Health Services (OHS) might make individual determinations that take into consideration factors that affect risk for transmission, such as the type and duration of contact (with a longer duration generally posing a higher risk than shorter), the risks of the exposed person for developing infection, the type of personal protective equipment (PPE) used, and the ventilation of the area (e.g., whether they were in a small contained/closed airspace with less ventilation versus an open and better ventilated area). In general, for most viral respiratory pathogens, transient contact with an infectious person (e.g., walking past the individual in the hallway) is not considered an exposure.

Clinical features

Respiratory viral infections can typically cause similar signs and symptoms, which, in general, may include, but are not limited to, the acute onset of any of the following19:

  • Fever
  • Chills
  • Fatigue (tiredness)
  • Cough
  • Runny or stuffy nose
  • Decrease in appetite
  • Sore throat
  • Vomiting
  • New loss of taste or smell
  • Headache, muscle or body aches
  • Diarrhea
  • Weakness

Some adults are at greater risk for severe disease (e.g., hospitalization, intubation, admission to ICU) from viral respiratory pathogens, and risk factors can vary by pathogen. For SARS-CoV-2, influenza viruses, and RSV, there are many similar characteristics that increase risk for severe disease in adults, including increasing age (e.g., over the age of 60-65 years), having medical comorbidities (e.g., asthma, blood disorders, cardiovascular disease, cerebrovascular disease, chronic lung diseases, endocrine disorders including diabetes, liver disorders, renal disease), pregnancy (for SARS-CoV-2 and influenza viruses), and moderately to severely immunocompromised202122.

The incubation period (i.e., time from infection to symptom onset) varies for each viral respiratory pathogen. For example, for the SARS-CoV-2 Omicron variant, the incubation period is approximately 2-5.6 days23; and for influenza, it is typically 1-4 days24.

Determining how long an adult infected with a respiratory pathogen may be contagious is critical to informing the duration of work restrictions for HCP with a viral respiratory infection. A rapid review assessed the relationship between the duration of shedding and symptoms, and the duration of serial interval for SARS-CoV-2 Omicron variant and influenza A virus among previously healthy adults. The review found that most mildly ill adults will have stopped shedding influenza A virus and Omicron within 10 days of symptom onset, diagnosis, or viral inoculation. However, a small proportion will shed for longer. The review also used the serial interval to estimate the daily change in the risk of transmission from an infected adult. Based on this approach, the review reported most transmissions for both viruses occurred earlier in the course of illness; and once a person's symptoms began, at least 70% of transmissions occurred by the end of day 3, and at least 80% by the end of day 5, when measured from symptom onset in the infected person. Then, by the end of day 7 after a person's symptoms began, it was estimated that more than 90% of transmissions had occurred25.

The supplement to this document contains an update to the 2025 rapid review and a rapid review to assess the same outcomes for RSV infections.

Testing and diagnosis

HCP with mild symptoms of a viral respiratory infection may not be tested to confirm which pathogen is the causative agent, whereas testing may more likely be performed for those with severe illness or immunocompromise. In general, there are various types of tests for viral respiratory pathogens. Typical tests include antigen tests and nucleic acid amplification tests (NAATs) (e.g., polymerase chain reaction tests). Although antigen tests return results faster, NAATs are typically more reliable at detecting viruses, but may remain positive after a person is no longer contagious2627. Ultimately, how to test for a specific viral pathogen varies by virus, and information on recommended viral pathogen-specific tests can be found on the CDC website:

OHS personnel often use a combination of clinical judgement (i.e., suspicion of a viral respiratory infection) and acute respiratory illness (ARI) criteria to identify HCP without a confirmatory viral laboratory test as having a suspected viral respiratory infection. ARI is generally defined as the presence of two or more signs or symptoms, such as fever (subjective or objective), cough, runny nose or nasal congestion, or sore throat29.

Postexposure prophylaxis

In general, antiviral postexposure prophylaxis (PEP) is not routinely provided to HCP exposed to a viral respiratory pathogen. However, antiviral PEP, when available, may be recommended for HCP in certain circumstances, such as being at risk for severe disease or working in an area in a healthcare facility experiencing an outbreak of a viral respiratory pathogen. Information and recommendations about the use of antivirals for treatment or as PEP for some viral respiratory pathogens can be found on the CDC website:

Professional societies, such as the Infectious Diseases Society of America (IDSA Practice Guidelines)32, may also provide guidance on the use of antiviral medications for selected respiratory viral pathogens.

Considerations for when HCP return to work

Antiviral medications and receipt of vaccination may reduce the risk of transmission of some viral respiratory pathogens from infected HCP, but do not generally inform return to work decisions because limited data are available. There have been reports of a reduction in the duration of viral shedding in vaccinated adults who were mildly ill with COVID-193334, but this effect has not been consistently reported. Antiviral medications might reduce risk of transmission for some pathogens, but it is difficult to quantify by how long. For influenza, neuraminidase inhibitors have been shown to reduce viral shedding by 1-2 days3536.

Source control of potentially contagious individuals can reduce the risk for transmission to others in healthcare settings3738. However, the potential reduction in risk for transmission likely depends on how source control is implemented by HCP to ultimately protect others in a healthcare setting. Practices for implementing source control in HCP typically include:

  • Selecting source control that is comfortable, can be worn for extended periods of time, and effectively contains secretions.
  • Wearing source control consistently around patients/residents, colleagues, and visitors.
  • Taking private source control breaks away from all other people, including while eating and drinking.
  • Reminding HCP that source control does not replace recommended Personal Protective Equipment for Standard and Transmission-Based Precautions.

Severely to critically ill persons and immunocompromised persons with a viral respiratory infection may be contagious to others for longer than those with milder illness. Immunocompromised persons are discussed in more detail in the Immunocompromised HCP section39. Return-to-work decisions for these HCP are typically made by OHS on a case-by-case basis. Strategies used by OHS to inform the duration of work restrictions for HCP with viral respiratory infections who have been severely to critically ill or are immunocompromised typically include:

  • Consultation with an expert in pathogen transmission/immunosuppression (e.g., infectious diseases specialist) and
  • Considerations for using pathogen-specific testing to inform ongoing risk for transmission.
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Published:
Updated: September 11, 2026

This page was last updated on this date. Updates may include minor edits, image changes, or other modifications to page content.

Reviewed: September 11, 2026

The information on this page was last reviewed by subject matter experts to ensure accuracy.

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