The best shot at a vaccine may not even be that great
Many of the vaccines scientists are looking at may not reach the ‘one-shot’ standard
Two important studies on the human immune response to Covid-19 infection are causing scientists to reassess how vaccines might work and be delivered.
Hopes remain that a “one shot and you’re protected for life” vaccine will still emerge, but the more we learn about the immune response, the less straightforward that seems.
It is more plausible, say experts, that the first Covid vaccines will be time-limited, requiring booster shots every few years. Others may only relieve the worst of the symptoms. The first of the new studies shows that the protective antibodies fade relatively quickly from the blood – just as they do with other coronaviruses...