As many scientists consider Covid as a seasonal disease, likely cyclically, would we have to get yearly booster shot, like against influenza, which seasonality is similar? A question INSERM scientist and infectious disease specialist Odile Launay tried to answer to on LCI.
And the answer is not crystal clear: “it’s not the same specific case as with flu, for which people get vaccinated again mostly to adapt to new strains” she explains. A first-draft response raising another question: “would today’s allowed vaccines – which action aims at the spike protein – require us to get vaccinated again to adapt our immune response?”, she wonders. It is possible given the vaccine has already changed and seems – in some cases – less sensitive to vaccine. We can think of the South African variant on which vaccines seem to be less effective.
Another question one can raise: “how long will vaccine immunity last?” According to the infectious disease specialist, it “seems longer than flu, including long-term protection”. But variants might make a big difference… “We’ll get more elements in the coming months”, Launay explains. She goes on: “With AstraZeneca vaccine, effectiveness seems weaker on the South African variant […] as for RNA ones or the one developed by Janssen drugmaker they do not grow weaker”.
A booster shot seems likely in the coming years but not on a yearly basis: “we yet speak about vaccines more effective than flu vaccines: we go from higher in terms of protections and antibody concentration aimed at the virus thanks to vaccine” the infectious disease specialist adds. For instance, “booster shot against diphtheria, tetanus, and polio” are given “every 20 to 10 years” and they cycles may be similar, or even closer. She concludes “no one can predict the precise impact of vaccines”.