Medically speaking, the account is strangely incomplete, especially since the specific strain wasn't mentioned. The USA annual influenza vaccine only include

Medically speaking, the account is strangely incomplete, especially since the specific strain wasn't mentioned. The USA annual influenza vaccine only includes 2 or 3 strains, and those are selected many months before flu season. It's guesswork at best. I've never even heard of them reworking a given year's vaccine even when they know the choices were inappropriate for the actual vectors that year.