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Coronavirus Disease 2019

Skilled Nursing Facility Guidelines for Influenza Prevention and Control in the Context of COVID-19

Summary of Recent Changes

Note: On January 9, 2024, both CDPH and Cal/OSHA updated the State Public Health Officer Order for COVID-19 Disease Control and Prevention and related guidance documents for the general population and the COVID-19 Prevention Non-Emergency Regulations for workplaces, respectively.

Our local COVID-19 guidance for Skilled Nursing Facilities (SNFs) remains unchanged and more protective. The infectious period for COVID-19 transmission has not changed. Because of the congregate living arrangements in SNFs, the risk of COVID-19 transmission remains higher in these settings compared with the general population. In addition, there is a high prevalence of certain medical conditions associated with severe COVID-19 among people residing in SNFs, increasing the risk for severe outcomes from COVID-19 in this population.

Per Cal/OSHA, all individuals with COVID-19 need to wear a well-fitting, high-quality mask for a total of 10 days after their symptoms began or, if they do not have symptoms, the date of their initial positive test, whenever they are around others. This includes individuals who test positive or are diagnosed with COVID-19 and have no symptoms or only mild symptoms.

Currently, staff at all licensed healthcare facilities, including Skilled Nursing Facilities, are required to receive the current season’s flu and updated COVID-19 vaccination or wear a respiratory mask for the duration of respiratory virus season while in contact with residents or when in any resident care area in the facility. Additionally, when the CDC designated Los Angeles County COVID-19 Hospital Admission Level meets or exceeds the Medium Level, all staff, regardless of vaccination status, and visitors in licensed inpatient health care facilities, including Skilled Nursing Facilities, are required to wear well-fitting masks while in contact with residents or when in any resident care area in the facility. This will be under review when the CDC designated Los Angeles County COVID-19 Hospital Admission Level has been at Low for at least 14 consecutive days.

Note: Where differences exist between the most current Federal, Cal/OSHA, CDPH, and LA County guidelines and requirements, SNFs are to follow the most protective guidance and requirements.


During the viral respiratory illness season that typically begins in late fall and continues through early spring, skilled nursing facilities (SNFs) observe an increase in the number of residents experiencing respiratory symptoms. There are many viruses that can cause respiratory illness including, but not limited to, influenza, respiratory syncytial virus (RSV), and SARS-CoV-2 (the virus that causes COVID-19).

Optimal management of potential viral respiratory illnesses in SNFs will depend on many factors, such as suspicion or detection of single or concurrent viruses and a facility’s ability to separate persons with confirmed/suspected infection(s). It can be challenging to appropriately cohort symptomatic residents and their close contacts if private rooms are not available. Managing a resident who develops acute symptoms compatible with a viral respiratory illness can be further complicated if timely access to diagnostic testing is not available. It is not possible to provide prescriptive or standard recommendations that can be applied across all settings. Therefore, facilities must understand and adapt the principles and framework described in this document for testing and managing persons with an acute respiratory illness of suspected infectious etiology. Additionally, Los Angeles County Department of Public Health (LAC DPH) provides consultation and tailored recommendations for facilities experiencing suspected and confirmed outbreaks.

These guidelines focus on management of influenza in the context of COVID-19*. This is because influenza and SARS-CoV-2 are the viral respiratory pathogens that are associated with the greatest morbidity and mortality in the SNF population. In addition, both are vaccine preventable diseases with effective therapeutic options.

*COVID-19 specific guidance for SNFs is more fully detailed in the LAC DPH Guidelines for Preventing and Managing COVID-19 in SNFs.


Vaccination is the single best preventive measure. Ensuring high facility-wide vaccine coverage among residents and staff for both influenza and COVID-19 can substantially reduce the risk of experiencing an outbreak. For individuals, vaccination can significantly reduce the risk of hospitalization, admission to the ICU, and death. Prior to the start of every respiratory virus season, facilities should ensure that residents are up to date with their vaccinations against influenza, COVID-19, pneumococcal pneumonia*, and RSV. All residents should be offered the influenza and COVID-19 vaccines for the current season or have documentation indicating reason for declination. The goal is for all staff and all residents to get and stay up to date on their recommended vaccines.

As a part of their occupational or employee health program, every SNF should also offer the influenza vaccine and the COVID-19 vaccine for the current season to all staff members before every respiratory virus season, as well as the RSV vaccine for certain staff members (e.g. pregnant persons, staff above 60 years of age) when recommended. Facilities should have established policies and procedures to ensure that staff either receive both the influenza vaccine and the COVID-19 vaccine for the current season, or mask for the entirety of the respiratory virus season, as required by the Los Angeles County Health Officer Order (HOO). Additional resources, including FAQs about the Health Officer Order, can be found here. Additionally, starting with the 2022-2023 season, SNFs are required to report their healthcare personnel influenza vaccination coverage to the National Healthcare Safety Network (NHSN) per the Centers for Medicare and Medicaid Services (CMS). Technical assistance on this reporting requirement can be found from Health Services Advisory Group (HSAG).

Please note that co-administration of more than one vaccine in the same clinic is allowed and encouraged to avoid missed opportunities or delays in vaccination since many of the above-mentioned vaccines are time-sensitive and should be given before the respiratory virus season (influenza, COVID-19, RSV). If vaccines are co-administered, they should be administered at different anatomic sites as per the ACIP General Best Practice Guidelines for Immunization (see “Multiple Injections” under the Vaccine Administration section). Additional resources for healthcare professionals are available from the CDC and for long-term care settings from the Immunization Branch of CDPH.

*An additional tool for healthcare providers to determine the recommended pneumococcal vaccine for their patient is provided by the CDC: PneumoRecs VaxAdvisor.

Surveillance and Outbreak Reporting

During the respiratory virus season*, a key component of respiratory virus surveillance is active daily symptom screening, followed by prompt diagnostic testing of residents who screen positive. This serves as surveillance both for influenza and COVID-19. Prompt diagnostic testing for both influenza and COVID-19 should be immediately performed for residents with acute respiratory illness.

The symptoms of influenza and COVID-19 significantly overlap, making it difficult to distinguish between the two and other respiratory viral illnesses based on symptoms alone. As a reminder, the signs and symptoms of acute respiratory illness common to both influenza and COVID-19 are: fever (≥100°F or 37.8°C), cough, shortness of breath, sore throat, chills, headache, myalgia (muscle pain or body aches), fatigue (tiredness), runny or stuffy nose, vomiting, and diarrhea. Please note that some persons, such as older adults and individuals with immunocompromising conditions, may have atypical clinical presentations, including, but not limited to, the absence of fever, for both influenza and COVID-19.

Promptly identifying respiratory viral illnesses will inform outbreak management decisions such as the appropriate isolation of infected residents and starting antivirals for treatment and prevention. While single cases of non-COVID-19 respiratory viruses (influenza, RSV, etc.) are not reportable to LAC DPH, outbreaks of any respiratory virus are reportable to LAC DPH per Title 17, Section 2500, California Code of Regulations. The outbreak definition for influenza and other non-COVID respiratory viruses:


  • At least one case of laboratory-confirmed influenza in the setting of a cluster (≥2 cases) of influenza-like illness (ILI) within a 72-hour period.
  • ILI is defined as fever (≥100°F or 37.8°C) plus cough and/or sore throat, in the absence of a known cause other than influenza. Persons with ILI often have fever or feverishness with cough, chills, headache, myalgia, sore throat, or runny nose. Some persons, such as the elderly, may have atypical clinical presentations, including the absence of fever.

Other non-influenza, non-COVID-19 respiratory viruses:

  • At least one case of a laboratory-confirmed respiratory pathogen, other than influenza or COVID-19, in the setting of a cluster (≥2 cases) of acute respiratory illness (ARI) within a 72-hour period.
  • ARI is defined as an illness characterized by any two of the following: fever, cough, rhinorrhea (runny nose) or nasal congestion, sore throat, or muscle aches.
  • Additionally, sudden increases in acute respiratory illness cases over the normal background rate, in the absence of a known etiology, must also be reported to LAC DPH. Suspected outbreaks in SNFs must immediately be reported to LAC DPH by emailing: ACDC-MorbidityUnit@ph.lacounty.gov, or by calling 888-397-3993 or 213-240-7821 as noted in the LAC DPH Reportable Diseases and Conditions list.


  • At least one asymptomatic or symptomatic resident, laboratory confirmed by molecular test, OR at least one symptomatic resident with positive antigen test for SARS-CoV-2.
  • The resident must have been a resident of the facility for at least 7 days.

*While the respiratory virus season typically ranges from November through March every year, the best way for facilities to stay up to date on local respiratory virus trends is by signing up for Los Angeles County’s respiratory virus surveillance report “RespWatch”, which is sent out weekly . To sign up, email "Subscribe Resp Watch" to influenza@ph.lacounty.gov or visit this page. Additionally, the CDC updates national influenza surveillance data in their Weekly U.S. Influenza Surveillance Report.

Diagnostic Testing

Individuals who have signs and symptoms of acute respiratory illness are suspected for influenza as well as COVID-19 during the respiratory virus season, and should immediately undergo diagnostic tests to determine if they are confirmed cases of influenza (symptomatic individuals with a positive diagnostic test), COVID-19*, or both. If RSV is circulating, consider using a molecular test that includes RSV in addition to influenza and SARS-CoV-2. It is not recommended to test asymptomatic individuals for influenza, RSV, or other non-COVID-19 respiratory viruses.

A variety of influenza diagnostic tests are available. It is important to understand the limitations of influenza virus tests and how to properly interpret the results. There are two categories of diagnostic tests for the detection of influenza viruses in respiratory specimens:

  1. Molecular assays including rapid molecular (viral RNA or nucleic acid) assays and laboratory-based reverse transcription polymerase chain reaction (RT-PCR).
  2. Antigen detection tests including rapid influenza diagnostic tests (RIDTs) and immunofluorescence assays.

CDC recommends using molecular assays, including rapid molecular assays and laboratory-based RT-PCR, for diagnostic testing in institutional outbreaks because of the low to moderate sensitivity of antigen detection assays (i.e., antigen tests have a higher likelihood of false negatives). Rapid antigen detection assays can be used if rapid molecular assays are unavailable or laboratory-based molecular assay results are pending. However, negative antigen test results in symptomatic individuals must be confirmed with a molecular assay (RT-PCR) for both influenza and COVID-19.

If two or more residents are ill, symptomatic individuals with ILI or acute respiratory illness who test negative for both influenza and SARS-CoV-2 using molecular-based tests (nucleic acid amplification tests including PCR) can then be tested for other respiratory pathogens, including bacterial or viral etiologies (such as RSV), based on what is known or suspected to be circulating in the community. Multiplex assays or laboratory-based respiratory viral panels can be used.

*COVID-19 diagnostic testing is described separately in the LAC DPH Guidelines for Preventing & Managing COVID-19 in SNFs.

Influenza Outbreak Management in the context of COVID-19

Containing an influenza outbreak and mitigating morbidity depends on three key activities: 1) early identification of infected residents and staff (please see “Surveillance and Outbreak Reporting” above), 2) early initiation of antiviral influenza therapy for residents with suspected or confirmed influenza and chemoprophylaxis for exposed residents, and 3) optimal isolation of residents with suspected or confirmed influenza.

Early identification of influenza

All SNFs should be conducting daily proactive surveillance (symptom screening) of staff and residents as required for COVID-19. Daily surveillance of residents should also include temperature checks and oxygen saturation. All residents with signs and symptoms of acute respiratory illness should immediately be tested for both influenza and SARS-CoV-2, preferably at the same time to avoid delays in diagnosis. Please see “Diagnostic Testing” section above for more details.

Early initiation of influenza antiviral treatment and chemoprophylaxis


All SNF residents with suspected or confirmed influenza should be started on antiviral treatment within 48 hours of symptom onset. Treatment should not be delayed pending test results for residents with strongly suspected influenza unless there is a confirmed active COVID-19 outbreak in the facility. Influenza should be strongly suspected in a resident with acute respiratory symptoms if 1) there are other persons with confirmed influenza at the facility or 2) LA County respiratory virus surveillance data indicate an increase in Countywide transmission of influenza. Oseltamivir is the most commonly used antiviral medication, but other options include oral baloxavir, inhaled zanamivir, and intravenous peramivir. See CDC, Influenza Antiviral Medications: Summary for Clinicians for more information.


Chemoprophylaxis refers to the use of antiviral medications to prevent influenza in asymptomatic persons either pre- or post-exposure. Oral oseltamivir is the preferred antiviral for chemoprophylaxis, but inhaled zanamivir is also an option. Please see CDC, Influenza Antiviral Medications: Summary for Clinicians for more information. If symptoms develop, individuals should receive treatment dosing (see above).

  • Asymptomatic residents should be offered chemoprophylaxis in the following situations, regardless of vaccination history:
    • All of the roommates of a resident with confirmed influenza infection should be started on oseltamivir chemoprophylaxis.
    • If influenza infection is confirmed in a second resident who was not a roommate of the first case, antiviral chemoprophylaxis should be started for all residents in the outbreak-affected unit/wing.
    • If there are cases in multiple units/wings, then chemoprophylaxis should be provided for all residents in the facility regardless of vaccination history, with priority given to the roommates of the confirmed cases when there is a shortage of antivirals.
  • Chemoprophylaxis can be considered for asymptomatic healthcare personnel (HCP) when the facility has an outbreak of influenza in the following situations:
    • If they are unvaccinated; OR
    • If they received an inactivated influenza vaccine within 14 days prior: OR
    • If evidence indicates that the circulating influenza viruses are not well-matched to the seasonal influenza vaccine, regardless of HCP vaccination history; OR
    • If there is a risk of short staffing in facilities and units where HCP are limited and to reduce HCP reluctance to provide care to residents with suspected or confirmed influenza, regardless of HCP vaccination history.

SNFs experiencing a shortage or a low supply of oseltamivir

When there is a limited supply of oseltamivir, then the treatment of residents with suspected and confirmed influenza should be prioritized over the chemoprophylaxis of asymptomatic persons.

If there is a remaining but limited supply of oseltamivir for chemoprophylaxis, it is recommended that SNFs prioritize chemoprophylaxis for roommates of suspected/confirmed cases and consider use of inhaled zanamivir or oral baloxavir in addition to, or in place of, oral oseltamivir. Please see CDC, Influenza Antiviral Medications: Summary for Clinicians for more information.

Residents not receiving chemoprophylaxis as recommended (see above) should be closely monitored for the development of fever and/or respiratory symptoms. If symptoms develop, empiric therapy should be provided as soon as possible without waiting for laboratory confirmation.

Facilities should continue to secure additional supply and can utilize and/or share with their long-term care pharmacy this resource from the Food and Drug Administration (FDA): Availability of Antiviral Medications. If there are any issues or questions regarding oseltamivir supply, please do not hesitate to contact Public Health at LACSNF@ph.lacounty.gov.

Optimal isolation of residents with suspected or confirmed COVID-19 and/or influenza

Appropriate isolation of residents with suspected or confirmed influenza can be logistically challenging given the multiple permutations of residents who could have influenza, COVID-19, coinfection with both viruses, and/or infection with some other respiratory virus.


Below is a brief summary of COVID-19 isolation recommendations. For full details, please refer to Isolation and Quarantine section of the LAC DPH Guidelines for Preventing and Managing COVID-19 in SNFs.

  • Residents with confirmed COVID-19 infection, including asymptomatic should isolate for 10 days (after symptom onset or positive test, respectively) in a designated COVID-19 isolation area (formerly Red Zone), ideally in a private room. Confirmed COVID-19 is defined as symptomatic residents with a positive viral test (PCR/NAAT or antigen) or asymptomatic residents with a positive molecular (PCR/NAAT) test.
  • Residents with suspected COVID-19 should isolate in-place in their current rooms. Suspected COVID-19 are symptomatic residents with pending/unknown test results or asymptomatic residents with a positive antigen test pending confirmatory PCR/NAAT testing.
  • Asymptomatic residents who are close contacts or who were in the same unit or wing where an individual with infectious COVID-19 was identified should remain in their current rooms unless movement is necessary to create or expand the designated COVID-19 isolation area. Quarantine (restricting the resident to their room as much as possible if safe and practical; resident wearing masks indoors when not in their rooms; staff donning the full set of personal protective equipment [PPE] per COVID-19 transmission based precautions) may be required if directed by Public Health during an active COVID-19 outbreak investigation.


The guidance for isolation for influenza differs from COVID-19 because compared with COVID-19, influenza tends to be less contagious, the morbidity is lower, and there are antivirals authorized as chemoprophylaxis to mitigate influenza spread.

  • For confirmed cases of influenza in residents (symptomatic with positive diagnostic test results), unlike COVID-19, it is not necessary for facilities to dedicate a physically separated space for isolation. Facilities should consider isolating residents with confirmed influenza in private rooms where available.
  • Symptomatic residents who are waiting for influenza testing results should be empirically isolated on the most protective transmission-based precautions (e.g., COVID-19 precautions), preferably in private rooms if available. When private rooms are unavailable, then symptomatic residents should isolate in-place, remaining in their current rooms on the most protective transmission-based precautions. Subsequent management will follow either the influenza or COVID-19 guidance as indicated by the testing results.
  • If a symptomatic resident is only confirmed to have influenza and is negative for COVID-19, then the empiric COVID-19 transmission-based precautions can be transitioned to droplet precautions. Duration of droplet precautions is at least 7 days from illness onset or until symptoms have improved and the resident is fever free for at least 24 hours without fever reducing medications, whichever is longer.
  • Hospitalized patients with influenza can be discharged to a SNF when clinically appropriate and should be continued on droplet precautions; the duration of droplet precautions is the same as above and does not need to be restarted upon admission to the SNF. Please note that standard precautions should always be followed regardless of the infectious pathogen.
  • In multi-occupancy rooms, ensure spatial separation of at least 6 feet and privacy curtain between residents. In facilities that do not have 6 feet of space between residents, separation should be as close to 6 feet as possible, but no less than 3 feet. Regardless of outbreak status, staff should always treat each bed space as a separate room and doff their used PPE and don a new set of PPE when caring for the next resident in the same multi-occupancy room. Dedicated staff should be used to care for COVID-19 positive residents but are not necessary for influenza positive residents.

Respiratory syncytial virus (RSV)

Droplet, contact, and standard precautions are recommended and should be continued until symptoms have improved and the resident is fever free for at least 24 hours without fever reducing medications. Please see LAC DPH’s homepage on RSV for more updated information.

Other Outbreak Control Measures
Managing Healthcare Personnel During an Influenza Outbreak

Facilities should encourage staff to get the influenza vaccine if they have not already received it. Influenza infected staff should be excluded from work for at least 7 days after symptom onset or >24 hours after symptom improvement and the individual is fever free without fever reducing medications. Staff with suspected or confirmed influenza should promptly seek medical care to determine if antiviral treatment is appropriate, regardless of vaccination history. Asymptomatic staff may be offered antiviral chemoprophylaxis if indicated as described above.

Personal Protective Equipment (PPE)

In the context of the current COVID-19 pandemic, standard precautions, including well-fitting face masks, are required for caring for all SNF residents, regardless of the presence of influenza. When caring for residents with a new acute respiratory illness, an N95 respirator should be worn as a part of COVID-19 transmission based precautions until test results are returned and COVID-19 is excluded. See Infection Prevention and Control Guidance section of the LAC DPH Guidelines for Preventing and Managing COVID-19 in SNFs for more information.


In addition to required use of face masks by healthcare personnel and visitors, residents are strongly encouraged to wear well-fitting face masks when they are outside their room throughout the respiratory virus season.


There are currently no general restrictions to visitation for either influenza or COVID-19 outbreaks in SNFs. Visitors should be made aware of any outbreaks occurring at the facility, including influenza and COVID-19. Facilities can do this by posting signage at entrances and sending out communication (letters, emails, texts) to families and visitors. They should also be counseled on their risks of visiting residents who are suspect or confirmed cases of influenza or COVID-19 and should follow healthcare personnel instruction on proper donning and doffing of PPE when applicable. Additional COVID-19 guidance for visitors may apply; please see the Communal Dining, Group Activities, and Visitation section of the LAC DPH Guidelines for Preventing and Managing COVID-19 in SNFs.

Concurrent Influenza and COVID-19 Outbreak Management

If there are concurrent influenza and COVID-19 outbreaks, then the facility should prioritize implementing isolation, PPE use, and other infection control precautions as recommended for COVID-19. If a resident is concurrently diagnosed with influenza and COVID-19 by molecular testing for both viruses, then the resident should ideally be placed in a private room in the COVID-19 Red Zone. If there are not sufficient private rooms in the Red Zone, then consider cohorting “like with like.” Below are examples of cohorting “like with like”:

  • A resident with a confirmed influenza infection is isolated in the same room with other residents who are confirmed to only have influenza infections.
  • A resident with confirmed co-infections of influenza and COVID-19 are isolated in the same room with other residents with confirmed co-infections of influenza and COVID-19 in a designated COVID-19 isolation area (Red Zone).

In general, when there are simultaneous outbreaks of COVID-19 and another non-COVID respiratory virus (influenza, RSV), prioritize the isolation of confirmed COVID-19 cases and avoid movement of residents based on influenza status that could worsen COVID-19 transmission. Similarly, dedicated staffing should be prioritized for the designated COVID-19 isolation area. The rationale behind prioritization of isolation of residents and staff by COVID-19 status over influenza status is because influenza tends to be less contagious, the morbidity and mortality for COVID-19 is higher, and there are more approved pharmacological interventions for mitigating outbreaks of influenza.

Residents who are suspected or confirmed to have co-infections of influenza and COVID-19 should be started on antiviral treatments for both. Influenza antiviral treatment should be started as soon as possible and within 48 hours of symptom onset, even before testing confirmation when suspicion is high (empiric treatment). COVID-19 antivirals, e.g., ritonavir-boosted nirmatrelvir (Paxlovid), should be started in symptomatic persons as soon as testing results confirm infection and within 5 days of symptom onset. Please see Outpatient COVID-19 Treatment and Pre-exposure Prophylaxis in the LAC DPH Guidelines for Preventing & Managing COVID-19 in SNFs for more details. LAC DPH’s COVID-19 Therapy for Non-Hospitalized Patients for healthcare providers is another helpful resource. Antiviral regimens for influenza treatment are the same for all individuals regardless of SARS-CoV-2 co-infection.

Please note that while Paxlovid can alter the concentration of some drugs, there are no clinically significant drug-drug interactions between the outpatient treatment options for COVID-19 and the influenza antiviral agents. In addition, Paxlovid can be safely co-administered with many commonly used medications despite its drug-drug interaction potential. The Infectious Disease Society of America offers guidance on simple steps that can be taken to avoid significant interactions with commonly prescribed medications, such as brief suspension or dose reduction. See NIH guidance Drug-Drug Interactions Between Ritonavir-Boosted Nirmatrelvir (Paxlovid) and Concomitant Medications and the Liverpool COVID-19 Drug Interactions website.

Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.

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