They were part of that operation Warp Speed, and were able to work quickly because Trump was cutting red tape. But they're having a hissy fit because he's not allowing them to overcharge Americans for drugs anymore, so they deliberately withheld this vaccine info until after the election.

There is a not-insignificant number of people still very frightened by the flu panic who believe the news about Trump "doing nothing," so this news would have been reassuring and pumped up his numbers even more. They deliberately influenced the election.