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State of California—Health and Human Services Agency
California Department of Public Health

July 28, 2023

Staff in Healthcare Settings

Guidance for Face Coverings as Source Control in Healthcare Settings



High-quality, well-fitting face masks are effective at reducing the risk of transmission of respiratory infections (including COVID-19) and are an important component of a comprehensive strategy to reduce the risk of illness, hospitalization, and death from COVID-19 and other respiratory infections. Masks can provide both source control and personal protection within healthcare settings.

This document is intended to provide information that California healthcare settings should consider when developing and implementing their own facility-specific plans about face masking for source control, based on their patient population, facility considerations, and respiratory virus transmission metrics. The Centers for Disease Control and Prevention (CDC) provides additional recommendations for facilities on when to implement broader use of source control masking. Local health jurisdictions and other entities may implement requirements that go beyond this statewide guidance based on local circumstances.

In the workplace, employers are subject to the Cal/OSHA COVID-19 Non-Emergency Regulations or in some workplaces the Cal/OSHA Aerosol Transmissible Diseases (ATD) Standard (PDF) and should consult those regulations for additional applicable requirements.  ​​

This source control masking guidance is intended to be implemented in addition to other respiratory infection prevention measures, including immunizations for COVID-19 and other respiratory diseases, which remain the most effective strategy in preventing infection, disease, and serious illness and death from COVID-19.​​

Considerations for healthcare facilities when assessing local circumstances and developing their own plans to recommend or require source control masking in healthcare settings

Source control masking involves the use of well-fitting facemasks or respirators to cover a person's mouth and nose to prevent spread of respiratory secretions when they are breathing, talking, sneezing, or coughing. The use of masks by healthcare personnel (HCP)​ for source control of respiratory infections in healthcare settings serves two purposes:

  1. Source control to protect patients/residents: prevent HCP from infecting patients or residents, especially those who are unable to wear masks to protect themselves or have higher risk of severe illness or death from infection.
  2. ​Source control to protect co-workers: prevent HCP from infecting other HCP when they are not otherwise wearing respirators.

Local circumstances that healthcare facilities may consider when developing plans regarding source control masking for HCP include (but are not limited to):

  • Vulnerability of patient/resident population to COVID-19, influenza, and other respiratory infections.
  • Ability to maintain staffing levels if multiple staff were out sick with COVID-19, influenza, or other respiratory infections.
  • Local transmission of respiratory infections and COVID-19 hospital admission levels.
  • The impact of new viruses, variants, or strains on existing immune protection.

Multiple reports describe decreases in healthcare-associated respiratory infections temporally associated with source control masking [1][2]. Some infection control experts promote HCP masking as part of Standard Precautions for all patient encounters [3][4].

To promote patient/resident safety and prevent healthcare-associated transmission of respiratory infections, healthcare facilities may consider implementing source control mas king requirements for HCP during certain activities or times.

These may include requirements that HCP wear masks:

  • During all patient/resident interactions. 
  • In certain locations within the facility and patient/ resident populations, such as areas of the facility housing the patients or residents at highest risk.
  • During seasonal activity or increased community measures of COVID-19 and other respiratory infections (e.g. , influenza).
  • In the event of an outbreak or intra-facility transmission, elevated levels of patient/resident or HCP respiratory infections, or high levels of staff absenteeism. During this time, healthcare facilities may consider upgrading the level of source control and protection from a surgical mask to a fit-tested N95 respirator.

Source control masking for HCP following exposure to someone with COVID-19 infection

The California Department of Public Health (CDPH) continues to recommend that healthcare facilities require HCP who have had an ex​​​​posure to someone with COVID-19 infection and are working during their post-exposure testing period to wear an N95 respirator for source control at all times while in the facility until they have a negative test result on or after day 5.

In addition, all HCP who have a suspected or confirmed respiratory infection should stay home and not care for patients when ill. HCP who must remain at work with a suspected or confirmed respiratory infection may be required to mask for source control.  

Source control masking for HCP and vaccination requirements 

In jurisdictions or facilities where source control masking is required of all HCP in patient/resident care areas or interactions, additional requirements for un/under-vaccinated HCP could apply throughout the facility, including non-patient/resident care areas.​

Source control masking for visitors

Healthcare facilities may consider implementing source control masking policies for visitors based on the same local circumstances as for HCP as listed above, such as community transmission of respiratory viruses, emergent variants, and the number of ill staff.  

  • In general, visitors should be asked to defer their visit if they have symptoms of a respiratory infection or other communicable disease or have had recent close contact with someone with a COVID-19 infection within the last 10 days.
    • If visitation is essential (e.g., end-of-life), facilities should require that visitors wear a mask if they have respiratory symptoms, an infection, or have had a recent close contact with someone with a COVID-19 infection within the last 10 days.
  • For facilities such as skilled nursing facilities that may opt to implement masking policies for visitors, facilities cannot deny visitation (PDF) if a visitor refuses to mask[5].
  • In such a situation, the facility should offer alternatives such as an outdoor visit in a designated area and/or away from other patients.​ 

Voluntary use of respirators in situations where surgical masks are required for source control

In situations where surgical masks are required for source control, voluntary use of a respirator provides increased source control and protection for the wearer. This does not supersede any requirements for use of a respirator under Cal/OSHA COVID-19 Non-Emergency Regulations or the ATD Standard (PDF).​ ​


[1] Seidelman JL, DiBiase L, Kalu IC, Lewis SS, Sickbert-Bennett E, Weber DJ, Smith BA. The impact of a comprehensive coronavirus disease 2019 (COVID-19) infection prevention bundle on non-COVID-19 hospital-acquired respiratory viral infection(HA-RVI) rates. Infect Control Hosp Epidemiol. 2022 Jun 2:1-3. doi: 10.1017/ice.2022.137. Epub ahead of print. PMID: 35652146. 
[2] Woolbert ME, Spalding CD, Sinaii N, Decker BK, Palmore TN, Henderson DK. Sharp decline in rates of community respiratory viral detection among patients at the National Institutes of Health Clinical Center during the coronavirus disease 2019(COVID-19) pandemic. Infect Control Hosp Epidemiol. 2023 Jan;44(1):62-67. doi: 10.1017/ice.2022.31. Epub 2022 Feb 18. PMID: 35177161; PMCID: PMC9021590. 
[3] Kalu IC, Henderson DK, Weber DJ, Haessler S. Back to the future: Redefining "universal precautions" to include masking for all patient encounters. Infect Control Hosp Epidemiol. 2023 Feb 10:1-2. doi: 10.1017/ice.2023.2. Epub ahead of print. PMID: 36762631. 
[4] Palmore TN, Henderson DK. For Patient Safety, It Is Not Time to Take Off Masks in Health Care Settings. Ann Intern Med. 2023 May 16. doi: 10.7326/M23-1190. Epub ahead of print. PMID: 37186917.
[5] Centers for Medicare and Medicaid Services. Document of Your Rights and Protection as a Nursing Home Resident. (PDF) 2022 July 7. ​

Originally published on July 28, 2023​​