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Background

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.