The CDC has issued an influenza severe illness health advisory because of a sudden increase in reported cases. I have had several cases in our office this week. I wanted to offer some useful reminder information for use on the front-lines,

  1. Influenza A is the dominant seasonal strain; 98% sensitive to oseltamivir (Tamiflu).
  2. Tamiflu is optimally started within 3 days of symptom onset, but still of benefit after 5 days.
  3. Household and close contacts of documented flu-A cases should be given Tamiflu; 75mg/day x10 in adults (adjust for renal clearance, prn).
  4. Flu patients are contagious 1 day pre-symptoms and for about 7 days of illness (longer in kids).
  5. Rapid flu tests (antigen, not the molecular tests) are highly unreliable: average FALSE NEGATIVE 50-70% (range 10-80%, by brand). So,
    • If rapid test is negative, but flu is prevalent and the illness is consistent, treat with Tamiflu.
    • In the above high index-of-suspicion cases, have a reflex flu RT-PCR (viral genetic material) or culture test done.

    –  I always order “rapid flu test with reflex PCR, if negative”.

    • RT-PCR or culture are only 5-10% false negative.
  6. Vaccinate anyone coming through your facility just before and during flu season.
  7. Flu Signage/ Masks: On our entry and at the lobby window, during flu season, we post “It is Flu season. If you have had recent fever and respiratory symptoms, such as cough, runny nose, sore throat, and/or body aches, ask for a respiratory mask while you wait (N-95 mask).
    –  You protect your staff, yourself, and waiting patients, who may already be ill.
  8. Wash your hands frequently with soap and water or an alcohol-based rub.


If you have any ID-related questions, feel free to call.