Covid vaccine, third dose needed? What the experts say

How long does the Covid vaccine protection last? Will the third dose be given? When? And, above all, is it necessary? There are several questions, in light of the new increase in infections and the spread of the Delta variant. On the hypothesis of a third dose of the anti Covid vaccine after completing the vaccination cycle, “at the moment it is too early to confirm if and when it will be necessary” specify the European Medicines Agency (Ema) and the European Center for Prevention and disease control (ECDC), in a note. “There is still not enough data from vaccination campaigns and ongoing studies to understand how long the protection from vaccines will last, also considering the spread of variants”, remark the experts. “Any new evidence that will become available on this topic will be rapidly examined – ensure Ema and Ecdc – The data on the efficacy coming from ‘real life’ studies from Europe and other parts of the world are of particular interest to integrate the data clinical trials investigating booster doses “. “Vaccine manufacturers are studying the effect of what are called ‘boosters’, that is, the booster of a third dose of the” Covid-19 “vaccine that can be done in the fall, in the case of the loss of protection, both due to of the virus is due to too much time since vaccination. There are now people who have been vaccinated many months ago, in January-February. Once the data has been collected, we will see what the strategy for the third dose is “said Alessandro Vespignani , epidemiologist at Northeastern University in Boston, guest of ‘Radio Anch’io’ on Rai Radio 1. Virologist Fabrizio Pregliasco, professor at the State University of Milan, sees “the need for a third dose of” anti Covid “vaccine on immunosuppressed patients and in the RSA, however, the timing has yet to be decided “. “We must evaluate the opportunity on the most fragile – he explains to Adnkronos Salute – and on those who were vaccinated in the Rsa at the very beginning, in the first days”. As for doctors, now in contact with patients affected by variants of the virus, “there is still no certainty of the need for a recall”, but no fear. “I believe – believes the virologist – that the validity of the vaccine is superior and it is not the quantity of antibodies that determines immunity in a standardized and objective way”. “We have to do a study on antibody protection and go and see how long it lasts in people vaccinated” against Covid-19, because “so far conflicting data. Immune memory has millions of years of evolution and is important, but no one knows how to quantify it” says Massimo Ciccozzi , professor of medical statistics and epidemiology at the Campus BioMedico University of Rome, on the hypothesis of a third dose of vaccine. “I don’t know if it will be necessary. To date – Ciccozzi reminds Adnkronos Salute – everyone says no: the FDA says no, the EMA says no, the American CDCs say no, but Pfizer says’ I ad August I start the trial on 10 thousand people because the protein is slightly modified on the basis of the variants “. So I don’t know if it will be something necessary. After all – he reiterates – it is a new disease. The first vaccines were made in January, we still have to understand “. Pharmacologist Silvio Garattini explains that “there is no scientific basis for talking about a third dose of the anti Covid vaccine. It is the industry that talks about it. But to think of such a strategy we need a controlled clinical study which, at the moment, it has not been published. We do not know what the efficacy or toxicity may be. And then we need the approval from the EMA for the change of dosage. precise rules to safeguard everyone “underlines the founder and president of the Institute of Pharmacological Research Mario Negri Irccs to Adnkronos Salute. “There are several elements to evaluate. For example, how long the effectiveness of the completed vaccination lasts, evaluate the variants in circulation. The problem is very complex and a third dose does not solve everything. To date nothing tells us that it is really useful. It could be. , but to understand that we need experimentation. Industry would certainly do well. Fifty million people to be vaccinated is a lot of money, “says Garattini. Therefore, “we do not know if a third dose of the anti Covid vaccine will be needed. At the moment there are no elements to affirm this, but this possibility should be an incentive for Italy to be autonomous in producing the vaccine. We cannot depend on the industry. who presses for the third dose and then maybe does not give them to us or gives them to us with delay, as has already happened, unfortunately, in the first phase of the vaccination campaign “. Massimo Clementi, director of the Laboratory of Microbiology and Virology of the San Raffaele hospital in Milan and professor at the Vita-Salute University, at Adnkronos Salute observes that “it is still early to say whether the third dose of the anti Covid vaccine will be needed. At the moment I would say that the most important thing is to complete the vaccination program that we have given ourselves, and that is where we have to focus. There is a large slice of the Italian population to vaccinate and let’s not talk about the world one, given that some countries have very few vaccinated “. “We will then see what will happen in the autumn – he explains – How widespread the virus will be then, if it changes, what the epidemiology of the infection will be like. It will be necessary to consider all these things. And it is still early to say. Certainly for pharmaceutical companies to be able to take advantage over time knowing what they will have to do is better, but at this moment, I repeat, it is too early to talk about the third dose “.