“The need for boosters proves the vaccines are useless.”

This is yet another misunderstanding about the long history of vaccination. Scientists have been clear about the possibility that extra vaccine doses beyond the original schedule might be needed for the coronavirus, even before the vaccines were released to the public. And while every germ (and our immune response to it) is different, it turns out that third doses and boosters are commonly needed for many of today’s vaccines.
Vaccines for hepatitis B and polio, among others, require a third dose months after their second dose to provide optimal immunity. The flu shot has to be taken yearly, on account of the flu’s ability to rapidly evolve. And even the combination measles, mumps, and rubella shot requires a dose to be given years after the first dose. Time will tell how often we’ll need a boost in protection from the coronavirus, but there’s nothing damning about the need for boosters in the first place.