Vaccines work even seven months after their administration. From the Higher Institute of Health comes an indication that may have significant implications also on the third dose matter. On the basis of a study that identifies cases of infection among those who are vaccinated, the Institute comes to the conclusion, precisely that in general population after 210 days from the second dose “there is no significant reduction in efficacy in terms of protection from infection, symptomatic or asymptomatic, which remains at 89%. Even against hospitalization and death, protection remains high, 96% and 99 %, six months after the second dose. First Aifa and then Ema have established that a third administration cannot be done before six months after the second. The European agency, however, has said that one can already think of that extra dose for over 18 while our country has foreseen it for now not for all citizens but only for particular categories. You can therefore expect to start with the third dose campaign.
The Institute does not work by observing the presence of antibodies in a sample of citizens. These tests are not considered reliable by the scientific community to assess the true ability of the organism to reject the virus. The work is based instead on epidemiology, that is, on the calculation of how many people vaccinated, and for how long, there are actually among those who become infected. This results in a “slight decrease in protection from infection in some specific groups”. In his report, which analyzed over 29 million people who have received at least one dose of the mRna vaccine, he notes that immunocompromesso there is “a reduction in the protective effect against infection from 28 days after the second dose”. This is an estimate that has some variability because it is based on a small number of cases. And yet the decision to start the campaign for the third dose already a few days ago seems right for this category of people (which can be done after 28 days from the second). Furthermore, “in people with comorbidities there is a reduction in protection from infection, from a 75% risk reduction after 28 days from the second dose to 52% after about seven months”.
The campaign for the third dose has recently started with regard to over 80 e i residents in the RSA. Well, for these people there has not been a major decline in protection. “The effectiveness against infection decreases slightly, while remaining above 80%,” writes the Higher Institute of Health. It means that there is not a significant increase in cases of the disease among those who have been vaccinated for longer than those who have recently been vaccinated. Furthermore, the Institute points out that, in general, the coverage has in any case changed with the Delta compared to when there was the Alfa variant. “Comparing the data between January and June 2021, the period in which the Alpha variant predominated, with those between July and August, with Delta prevalence, a reduction in efficacy against infection emerges from 84.8% to 67.1% . On the other hand, the effectiveness against hospitalizations remains high, 91.7% against 88.7% “. These data are different from that on the general population presented above, because they are analyzed with different methodologies. For example, they also take into account those who fell ill a few days after the first dose, and were therefore still susceptible because they were not covered by the vaccine, or who fell ill during an epidemic wave. If, on the other hand, the evaluation is made exactly seven months after the second dose, it is observed that 89% of people were protected by the vaccine.
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