Boosters are aptly named, they boost your antibody levels. You are correct the flu shot targets different strains, but the H1N1 strain has been part of the ann

Boosters are aptly named, they boost your antibody levels. You are correct the flu shot targets different strains, but the H1N1 strain has been part of the annual flu shot since 2009 simply because it has continued to circulate. So just like you get an H1N1 shot every year (to boost your antibody levels), you will likely get a COVID shot every year to boost those antibodies.