Current flu virus may mutate and evade vaccine, CDC warns

the Oncology Nurse Advisor take:

Although the flu season has just recently begun, the Centers for Disease Control and Prevention (CDC) issued a health warning about the current flu vaccine.

This vaccine prevents against three to four strains of the virus, but may not affect the H3N2 strain, which has infected most people but has mutated so that the vaccine won’t prevent the virus in half of the cases.

When flu viruses mutate, which happens quite often, they are called “drifts”, and since vaccines are formulated months in advance, they won’t protect well against these drifted viruses, but may provide cross-protection.

Although cross-protection won’t complete prevent the virus, it may help reduce the likelihood of severe outcomes, particularly for those at highest risk, including the elderly and very young children. The CDC still recommends everyone 6 months or older should receive the vaccine, despite the mutated strain.