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Health Officer Updates Previous Health Orders

DATE OF ORDER: September 19, 2023

EFFECTIVE DATE: November 1, 2023

Please read this order carefully. Violation of, or failure to comply with, this Order is a public nuisance subject to citation, abatement, or both, as well as a misdemeanor punishable by fine, imprisonment, or both. (California Health and Safety Code § 120295 et seq.; California Penal Code § 69, 148(a)(1)).


This Order requires all personnel in Patient Care Areas of Health Care Delivery Facilities to wear a Face Mask during the period deemed the Designated Winter Respiratory Virus Period by the Health Officer, with limited exemptions.


Annually, between late fall and spring, San Mateo County data shows higher rates of COVID-19, influenza, respiratory syncytial virus, and other viral infections that can cause severe respiratory disease among people living in the County.  This seasonal increase in circulation of multiple respiratory viruses causes a particular risk to populations more likely to experience severe disease and death if infected, including infants, older adults, and people with impaired immune systems. 

The seasonal surges also risk overwhelming the existing health care system in the county, jeopardizing the capacity to provide care for these and other diseases.  The risk to vulnerable patients of any of these viral illnesses in health care settings, including skilled nursing facilities, remains significant.  Vaccines and boosters that target respiratory viruses continue to be the best protection against severe disease. 

Another important protection in these settings is the use of a Well-Fitted Mask by Healthcare Personnel, which reduces both the risk of infection for those Personnel and reduces the risk of them transmitting respiratory viruses to Patients and Residents.  Considering the above, it continues to be important for masks to be used in the Patient Care Areas of these settings when seasonal risk of exposure to one or multiple viruses is at its highest. 

This Order introduces a new seasonal requirement for use of Face Masks in Health Care Delivery Facilities, as set forth below.



  1. Definitions.

    1. “Face Mask” means a surgical mask, KN95, KF94, or N95 that is well-fitted to an individual and covers the nose and mouth.  A scarf, ski mask, balaclava, bandana, turtleneck, collar, cloth mask, or any mask that has an unfiltered one-way exhaust valve does not qualify as a Face Mask under this Order.  Guidance regarding well-fitted masks may be found at
    2. “Health Care Delivery Facility” means a setting where patient care is provided indoors. Health Care Delivery Facilities include hospitals, dialysis centers, infusion centers, skilled nursing facilities, portions of long-term care facilities where nursing care is provided. 
    3. “Patient Care Area” means any area that patients regularly access in order to receive healthcare within a Health Care Delivery Facility.  Patient Care Areas include lobbies, waiting rooms, examination rooms, patient wings, elevators, and hallways used by patients.  Patient Care Areas do not include administrative offices or staff break areas that are only accessible to personnel of the Health Care Delivery Facility.  Patient Care Areas do not include areas such as cafeterias or gift shops that are not used for the provision of healthcare or to access areas where healthcare services are provided. 
    4. “Designated Winter Respiratory Virus Period” means the period from November 1 to April 30.  The Health Officer may adjust the dates of the Designated Winter Respiratory Virus Period based on respiratory virus surveillance data.  If the Health Officer changes the dates of the Designated Winter Respiratory Virus Period, the Health Officer will notify Health Care Delivery Facilities through a Health Advisory and a notice posted on the County Health Department’s website (
    5. “Personnel” means all paid and unpaid people who work in indoor Healthcare Facilities in locations where care is provided to patients.  This includes workers serving in healthcare or other settings who have the potential for direct or indirect exposure to Patients, Clients, Residents.  Personnel include, but are not limited to, nurses, nursing assistants, physicians, technicians, therapists, phlebotomists, pharmacists, students and trainees, contractual staff not employed by the Healthcare Facility, and persons who could be exposed to or transmit infectious agents that can be transmitted in the health care or congregate living setting (e.g., clerical, dietary, environmental services, laundry, security, engineering and facilities management, volunteer personnel and emergency services personnel).  “Personnel” does not include Patients, Residents or family members, friends and other individuals who enter healthcare facilities for the primary purpose of engaging in social visitation. 
  2. Mandatory Requirement to Wear Face Masks in Patient Care Areas of Health Care Delivery Facilities During the Designated Winter Respiratory Virus Period.
    1. Regardless of vaccination status, all personnel in Patient Care Areas of Health Care Delivery Facilities must wear a Face Mask during the period deemed the Designated Winter Respiratory Virus Period by the Health Officer, except for the following:
  1. Persons with a medical condition, mental health condition, or disability that prevents wearing a mask.  This includes persons with a medical condition for whom wearing a mask could obstruct breathing or who are unconscious, incapacitated, or otherwise unable to remove a mask without assistance.
  2. Persons who are hearing impaired, or communicating with a person who is hearing impaired, where the ability to see the mouth is essential for communication.
  3. Persons for whom wearing a mask would create a risk to the person related to their work, as determined by local, state, or federal regulators or workplace safety guidelines.
  4. Persons who are specifically exempted from wearing face masks pursuant to other CDPH guidance.

b. All businesses and governmental entities with Health Care Delivery Facilities must enforce this Face Mask Requirement for all healthcare personnel entering Patient Care Areas within the Health Care Delivery Facility, regardless of vaccination status, except as otherwise provided in this Order.  All such businesses and governmental entities must post clearly visible and easy-to-read signage at all entry points to Patient Care Areas to communicate the Face Mask requirements to all personnel entering the Patient Care Areas of the Health Care Delivery Facility.  

  1. In addition, those responsible for Health Care Delivery Facilities are required to provide Face Masks to individuals who will be in an area where Face Masks are required.
  2. This Order does not require patients, residents, and visitors to wear masks, although masks remain strongly recommended in healthcare settings for all patients, residents and visitors not covered by these requirements when interacting with others.

3. Recommendations from the Health Officer.  The Health Officer strongly urges all businesses and governmental entities with Health Care Delivery Facilities to monitor local and internal data that indicate circulating levels of respiratory viruses and impact to the facilities, such as, but not limited to, local virus wastewater monitoring, test positivity rates, bed availability, employee absenteeism due to illness, or rates of clinical care episodes due to respiratory viruses.  Health Care Delivery Facilities should institute internal policies that require masking at any time outside the Designated Winter Respiratory Virus Period when local or internal data indicate that there is a high level of risk to patients or employees.  It is also strongly recommended that personnel in healthcare facilities not listed in this order (e.g., outpatient clinics, mental and behavioral health clinics, therapy clinics, and residential care facilities for the elderly) wear well fitted masks when interacting with patients or clients during the winter respiratory virus season.

4. Applicability.  All individuals, businesses, and other entities in the county are ordered to comply with the applicable provisions of this Order.  For clarity, individuals who do not currently reside in the county must comply with all applicable requirements of the Order when they are in the county.  Governmental entities must follow the requirements of this Order applicable to Businesses, unless otherwise specifically directed by the Health Officer.

5. Obligation to Follow Any Stricter State Requirements.  If a conflict exists between this Order and any order issued by the State Health Officer, the Governor, or a State agency (such as the California Division of Occupational Safety and Health [Cal/OSHA]) related to promotion or protection of public health, the most restrictive mandatory provision controls.  For clarity, all individuals and entities must comply with any mandatory requirement imposed by the State to the extent it is stricter than any provision of this Order.  Consistent with Health and Safety Code section 131080 and the Health Officer Practice Guide for Communicable Disease Control in California, except if the State Health Officer issues an order expressly directed at this Order and based on a finding that a provision of this Order constitutes a menace to public health, any more restrictive measures in this Order continue to apply and control in this county.  In addition, to the extent any federal guidelines are inconsistent with this Order, this Order is controlling.

6. Enforcement.  Under Sections 26602 and 41601 of the California Government Code and Section 101029 of the California Health and Safety Code, the Health Officer requests that the Sheriff and the Chief of Police in the County ensure compliance with and enforce this Order.  The violation of any provision of this Order constitutes an imminent threat and immediate menace to public health, constitutes a public nuisance, and is punishable by fine, imprisonment, or both.

7. Effective Date.  This Order is effective at 12:01 a.m. on November 1, 2023.  This Order is ongoing and shall continue to be in effect until it is rescinded, superseded, or amended in writing by the Health Officer.

8. Copies.  Copies of this Order shall promptly be: (1) made available at 400 County Center, Redwood City, California; (2) posted on the County Health Services website ( ); and (3) provided to any member of the public requesting a copy of this Order.

9. Severability.  If any provision of this Order or its application to any person or circumstance is held to be invalid, the remainder of the Order, including the application of such part or provision to other persons or circumstances, shall not be affected and shall continue in full force and effect.  To this end, the provisions of this Order are severable.


Kismet Baldwin-Santana MD, MPH
Health Officer

Text of Order F23-1