The CDC reports that the vaccine failed miserably against a flu bug that popped up halfway through the season.
In fact — the agency rated its effectiveness at just 9% against that strain, and the overall effectiveness at 29%.
Flu vaccines are made each year to protect against three or four different kinds of flu virus.
The ingredients are based on predictions of what strains will make people sick the following winter.
Copyright © 2019 KABC-TV. All Rights Reserved.