If influenza vaccine effectiveness is questioned because staff report stomach flu, what action should the infection preventionist take?

• A. Screen patients and other workers for Norovirus
• B. Quarantine all staff with flu-like symptoms
• C. Provide antiviral prophylaxis to all patients
• D. Reassess vaccine quality with the manufacturer

Answer: (A)

When staff report stomach flu symptoms, the situation points to gastroenteritis rather than influenza. The influenza vaccine protects against influenza, not norovirus, so questioning vaccine effectiveness isn’t addressed by testing the vaccine itself. The best first step is to screen patients and coworkers for norovirus to see if a GI outbreak is occurring and to guide the right controls. If norovirus is suspected, implement GI precautions, ensure strict hand hygiene with soap and water (since alcohol-based sanitizers are less effective against norovirus), isolate or cohort symptomatic individuals as needed, exclude symptomatic staff until 48 hours after symptoms resolve, and intensify environmental cleaning with appropriate disinfectants. This targeted approach directly addresses the suspected pathogen and helps prevent further spread. The other options don’t fit the immediate issue: focusing on influenza-like illness would be inappropriate given GI symptoms; giving antiviral prophylaxis to all patients isn’t indicated for a presumed norovirus outbreak; and reassessing vaccine quality doesn’t address the actual source of transmission.