“For days we have been hearing more and more insistence about the ‘third dose’ of the” anti-covid “vaccine as if it were a foregone necessity to be prepared for. In reality, nothing is taken for granted”. Thus the immunologist of the University of Padua Antonella Viola in a speech in La Stampa. “First of all, we still don’t know how long the protection offered by the two doses (or the single dose in the case of the Johnson & Johnson vaccine) lasts.” “What we know for sure is that, 9 months after vaccination, people are still protected, he stressed – With the passage of time, we will be able to slowly move this deadline up to 1 or 2 years or even beyond. In the absence of data and with a little-known virus, making predictions seems rather complicated, as we do not know well the immune response that confers protection to the infection or, as they say in technical terms, the immunological correlates of protection are not yet completely clear ‘”. “Before deciding on the third doses, it would therefore be necessary to wait and evaluate the possible scenarios, which will also depend on the ability of the virus to mutate” he said. But “when we are all vaccinated, if even Sars-CoV- manages to overcome the first barrier and infect us, will we still be less vulnerable? Could Covid-19 therefore become truly ‘a trivial flu’? Is it possible and, as for the flu , it is possible that repeated vaccinations over time will be recommended to specific groups of people who are most at risk of developing a severe disease or who work in a context where the virus does not have to circulate, such as hospitals and nursing homes for the elderly. But, to date, we have only hypotheses and, as we know, it takes time for science to verify them “.