Ever since the first iteration of the COVID-19 vaccine, it seemed like no one was entirely sure how long to wait between booster shots — or exactly how many we should be getting.
Indeed, years later, all that is clear is that one series of shots is not enough. That's because SARS-CoV-2 is not the kind of virus (nor vaccine) that provides durable — meaning, lifetime — immunity; rather, it is, like influenza, a vaccine that confers only short-term immunity. Hence, like influenza, it seems that a new vaccine for COVID-19 each year, based on newly circulating variants, is the best public health protection.
