Influenza Information for Healthcare Professionals and Facilities

• CDC Influenza Infection Control in Health Care Facilities 
• CDC Seasonal Influenza Information for Healthcare Professionals

Follow the CDC guidelines and recommendations for the prevention of seasonal influenza in healthcare settings, including:  

• Encourage and administer seasonal influenza vaccine. Implement strategies to improve healthcare personnel influenza vaccination rates. 
• Promote good respiratory hygiene practices to patients, visitors, and healthcare workers. 
• Provide supplies (tissues, face masks, trash cans, alcohol-based hand sanitizer) to staff and in patient waiting areas and rooms. 
• Encourage people in common areas who have respiratory symptoms to sit as far away from others as possible or wear a surgical mask, when possible. 
• Triage incoming patients and if possible, have a separate waiting area equipped with the necessary supplies (tissues, face masks, trash cans, alcohol-based hand sanitizer) for patients with respiratory symptoms. 
• Implement droplet precautions for patients with confirmed or suspected flu. 
• Administer antiviral treatment and chemoprophylaxis to patients and healthcare personnel when appropriate.
• Healthcare workers and other staff with flu-like illness should stay home for at least 24 hours after fever has gone away (without the use of a fever-reducing medicine) and limit contact with other people. 
• More information on infection control in healthcare settings can be found on the CDC webpage. 

• CDC Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2024–25 Influenza Season  
• CDC Seasonal Influenza Vaccination Resources for Health Professionals 
• VDH Influenza Vaccination of Healthcare Personnel 
• Adverse event associated with influenza vaccination can be reported to the Vaccine Adverse Event Reporting System.

Role of testing in making treatment decisions 

• Diagnostic testing is not necessary for all patients with signs and symptoms of influenza to make treatment decisions.  
• Once influenza activity has been documented in the community or geographic area, a clinical diagnosis of influenza can be made for outpatients with consistent signs and symptoms , especially during periods of peak influenza activity in the community. 
• If influenza is suspected clinically and antiviral treatment is indicated, treatment should not be delayed while awaiting flu testing results. 
• Unsubtypeable influenza results should be sent to DCLS. 
• For more information see CDC Guide for considering influenza testing when influenza viruses are circulating in the community 

 Rapid influenza diagnostic tests 

• Rapid influenza diagnostic tests (RIDTs) can be useful to identify influenza virus infection. These tests produce very quick results in less than 15 minutes, but results need to be interpreted with caution. Sensitivity of these tests generally ranges from 50-70%, which means false negatives are common. False positive results are not as common (specificity ranges from  90-95%). 
• A negative RIDT result does not exclude a diagnosis of influenza in a patient with suspected influenza. 
• To minimize false rapid influenza diagnostic test results: 
  • Use RIDTs with high sensitivity and specificity. 
  • Collect specimens as early in the illness as possible (ideally less than 4 days of illness onset). 
  • Follow manufacturer’s instructions, including acceptable specimens and handling. 
  • Follow-up negative results with confirmatory tests (RT-PCR or viral culture) if a laboratory-confirmed influenza diagnosis is desired. 
• For more information see CDC Information for Clinicians on Rapid Diagnostic Testing for Influenza. 

 Other types of testing 

• Other testing (immunofluorescence, RT-PCR, viral culture) is more accurate but can take longer. Molecular tests are helpful in the identification of novel influenza viruses. 
• Patients suspected of having novel influenza infection require specialized testing that must be coordinated through your local health department. Relevant illness and severity criteria as well as exposure history criteria (such as recent travel to areas where novel human influenza infections have occurred or recent contact with swine, birds, or cattle) must be met before public health testing occurs. To learn more about specific testing criteria and specimen collection procedures, consult the CDC Interim Guidance on Testing and Specimen Collection for Patients with Suspected Infection with Novel Influenza A Viruses with the Potential to Cause Severe Disease in Humans. 
• Report any unusual influenza cases to your local health department. 

Antiviral resistance 

• Periodically throughout the influenza season, positive flu specimens are forwarded by public health laboratories to CDC for testing for resistance to oseltamivir and zanamivir. 

Additional testing information 

• CDC Information for Clinicians on Influenza Virus Testing webpage. for more information on clinical description and laboratory diagnosis of influenza, including a testing algorithm 
• Collection of Nasopharyngeal Specimens with the Swab Technique Instructional video 

Sentinel influenza surveillance testing 

Some clinicians participate in VDH’s sentinel surveillance program by collecting samples for confirmatory influenza testing at the state public health laboratory. These specimens help characterize the strains that are circulating in the community. If you would like to participate in sentinel surveillance, please contact your Local Health Department and speak to the district epidemiologist or the VDH influenza surveillance coordinator at flu@vdh.virginia.gov. 

•  Antiviral treatment is recommended as early as possible for any patient with confirmed or suspected influenza who: is hospitalized; has severe, complicated, or progressive illness; or is at increased risk for influenza complications.
  • Oral oseltamivir is the recommended antiviral for hospitalized patients or those with severe, complicated, or progressive illness. 
• Do not wait for laboratory confirmation of influenza when deciding whether to begin antiviral treatment. Empiric antiviral treatment should be started as soon as possible in the  groups listed above, ideally within 48 hours of symptom onset. 
• Providers can consider early empiric antiviral treatment of non-high-risk outpatients with suspected influenza (e.g., fever with either cough or sore throat) based on clinical judgement, if treatment can be initiated within 48 hours of illness onset. 
• Outpatients with complications or progressive disease and suspected or confirmed influenza (e.g., pneumonia, or exacerbation of underlying chronic medical conditions), should start  antiviral treatment with oral oseltamivir as soon as possible. 
• Outpatients with suspected or confirmed uncomplicated influenza, may be treated with oral oseltamivir, inhaled zanamivir, intravenous peramivir, or oral baloxavir, depending on approved age groups and contraindications. In one randomized controlled trial, baloxavir had greater efficacy than oseltamivir in adolescents and adults with influenza B virus infection (Ison, 2020). 
• Antiviral chemoprophylaxis should be used for prevention of influenza when indicated for institutional influenza outbreaks, and may be considered for those who have contraindications to influenza vaccination. 
• Patients who do not respond to antiviral treatment should be considered for antiviral susceptibility laboratory testing. 
• Antibiotics are not effective against influenza. See CDC’s website for more information on the appropriate use of antibiotics in the healthcare setting. 
• CDC Treatment Resources: 
  • Influenza Antiviral Medications 
  • CDC Health Advisory Interim Guidance for Clinicians to Prioritize Antiviral Treatment of Influenza in the Setting of Reduced Availability of Oseltamivir (December 22, 2022) 

Guidance 

• VDH Guidelines for the Prevention and Control of Influenza in Non-Healthcare Group Settings – applicable to assisted living facilities 
• VDH Guidelines for the Prevention and Control of Influenza in Nursing Homes and Long-Term Care Facilities During the COVID-19 Pandemic 
• CDC Interim Guidance for Outbreak Management in Long-Term Care Facilities 
• CDC Long-Term Care Quick Start Guide: Preparing for Respiratory Virus Season

Educational Resources

• VDH Quick Guide for Nursing Home Infection Preventionists: Influenza 
• VDH Influenza Fact Sheet

• For more information about current influenza activity levels and healthcare facility reporting requirements in Virginia, visit the VDH Flu website.
• CDC National flu activity and surveillance
• CDC Influenza A virus wastewater surveillance data
• VDH Healthcare personnel influenza vaccination reporting requirements for healthcare facilities