If immunity wanes, what does this mean for a vaccine? Will we have to get one yearly?
We don’t know the answer to this question at the moment. However, a vaccine that is effective and able to induce higher neutralizing antibody and T cell memory responses might protect for a few years. Although the coronavirus doesn’t mutate as quickly as the influenza virus, some scientists think that people might need to take a booster every two to three years. Also, others have suggested an annual vaccination.
Personally, I think we will need to take the vaccine every year, since even after exposure, a long-lasting immunity to the virus might not be developed.