Name:   GoneFishin - Subject:   70 years of flu vaccines...THE DIFFERENCE Date:   12/13/2020 8:01:04 PM

The flu has many differnt strains or variants and they have to make an educated guess as to which ones will strike that year. They then develop the vaccine based on those most likely to hit. The Covid vaccine was developed for one strain...Covid 19.

That explains the  lower percentage for the flu vaccine.

"The CDC released the interim report in advance of a meeting scheduled next week in Geneva, where vaccine experts from around the world will discuss what influenza strains should be included in next season's flu shot."