Several studies have found that over six months the effectiveness of mRna vaccines it is weaker. A premise, however, is a must: there is talk of effectiveness in curbing the contagion, not in the protection from hospitalization and especially from death, which remains very high both with Pfizer that with Modern, even in the event of contagion from Delta variant.
Given that mRna vaccines do the most important job very well, that of avoiding the development of the disease (a scientific certainty that should be enough and advance to convince everyone to get vaccinated, without resorting to the obligation), the data on the lesser effectiveness in curbing the contagion support the thesis that one may be needed third dose for some categories. Especially for the most fragile subjects and for doctors and health workers, who were the first to undergo the vaccination. According to data contained in a new study conducted by the New England Journal of Medicine, the effectiveness of the mRna vaccine in preventing infection dropped from 90% in March to 65.5% in July.
Obviously, the predominance of the Delta variant, combined with the end of restrictions and the greater sense of security of the population, meant that the protection against contagion offered by the vaccine fell. However, a certain difference between Pfizer and Moderna has emerged from various researches, with the latter appearing to offer a stronger and longer-lasting immune response: in Phase 3 studies it emerged that the efficacy of Pfizer dropped to 80% after four to six months, while Moderna remains at 93% after five to six.
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