Hi AskDr, my Doc did a swab for my flu that showed I was influenza positive and then started me on Tamiflu. How can this be when I have had my influenza vaccine before?

Hi @Lammmmmyyyy influenza is a type of virus with many strains. The influenza vaccine is regularly updated by medical authorities based on the relevant strains in epidemiologic studies. Therefore, it is possible that if you were vaccinated in the past but not recently this year, that your vaccination was not updated, i.e. you may be infected with a new/less common strain of influenza that you do not have immunity against. Hope you feel better soon!