 [ Symptoms ] i take zonisamide lyrica entocort ec maxalt and atenolol and now celexa are there any known drug interactions [ Disease ] not all viral infections are influenza so your self diagnoses may have been incorrect there are hundreds of different viruses that can cause flu like symptoms while the flu vaccine is not 100 protective especially this year it is possible to get another strain of influenza that is not covered by the vaccine influenza viruses can mutate and shift after the vaccine has been made so the viruses occasionally are one step ahead of the cdc