Covid Pfizer vaccine: new discovery on second dose and variant efficacy

Covid Pfizer vaccine: new discovery on second dose and variant efficacy
Covid Pfizer vaccine: new discovery on second dose and variant efficacy

The Pfizer vaccine produces lower levels of antibodies against the Delta variant, known as B.1.617.2 the cd. “Indian variant“: This is what a new study published in The Lancet states. The good news, however, is that the vaccine has proven itself effective against all Sars-Cov-2 variants after the second dose, even if it would leave people who have received only one more at risk.

I study

The research team analyzed the antibodies in the blood of 250 healthy people, aged 33 to 52, for up to 3 months after receiving the first dose of the Pfizer vaccine, focusing on “neutralizing antibodies” and the ability of antibodies to block virus entry into cells.

The researchers tested five variants: the original strain discovered in China, the dominant strain in Europe during the first wave in April 2020, the variant B.1.1.7 discovered in the UK, the variant B.1.351 first seen in South Africa and the most recent variant, variant B.1.617.2 discovered in India.

What emerged was that people who had been fully vaccinated with two doses of Pfizer they had 6 times lower antibodies against variant B.1.617.2, 5 times lower against variant B.1.351 and 2.6 times lower against variant B.1.1.7 than the original strain. The antibody response was even lower in people who received only one dose. After a single dose of Pfizer, 79% of people had neutralizing antibodies against the original strain, which dropped to 50% for variant B.1.1.7, 32% for variant B.1.617.2, and 25% for variant B. 1.351 variant.

Covid Pfizer vaccine: what changes with the second dose

The new discovery on the second dose of the Pfizer vaccine and its effectiveness against virus mutations turns out to be important because, in fact, it suggests one reduction of the time between one injection and the next.

“The most important thing is to ensure that vaccine protection remains high enough to keep as many people out of the hospital as possible,” said Emma Wall, PhD and lead author of the study and an infectious disease specialist at the hospital, in a statement. Francis Crick Institute in London. “And our results suggest that the best way to do it is quickly administer second doses and provide boosters to those whose immunity may not be high enough against these new variants ”.

As Roberto explained Burioni, what the study tells us is that “two doses induce antibodies which neutralize all variants of Sars-CoV-2 ”, while“ with only one no. And this could explain why the Brazilian and Indian variants are circulating in the UK ”.

“What emerges with great clarity – added Burioni – is that a single dose of Pfizer vaccine induces a good quantity of neutralizing antibodies against the ‘original’ virus in most of the vaccinated. On the contrary, that single dose of the vaccine does not induce such an effective response against the variants, in particular the Brazilian and the Indian “.

The virologist, summarizing the importance and the criticalities of this research, in Medical Fact, he finally concluded by explaining: “This work has limitations, the ability of vaccinated serum to neutralize viruses is analyzed and, as important as it is, this is not the only thing that protects. But it is a noteworthy idea, which reiterates that vaccinating with a single dose was not an idea without contraindications, as someone had already suggested many months ago “.

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