Why Pfizer and AstraZeneca’s protection has fallen over the years

CAs explained in an article published by BBC News, a survey conducted in the United Kingdom analyzed positive PCR test results between May and July 2021 of more than one million people who received two doses of Pfizer or AstraZeneca vaccine against the novel coronavirus.

In the study, the researchers found that protection after two doses of Pfizer diminished from 88% within one month to 74% within five to six months. However, among those who received the AstraZeneca vaccine, the decline was from 77% to 67% in four to five months. According to experts, such a decrease in protection was predictable.

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However, the researchers note that while infections do occur in fully immunized people, vaccines do an excellent job of protecting populations from severe Covid and reducing deaths from the disease.

According to BBC Public Health England, the British government’s public health agency, about 84,600 deaths and 23 million infections have been prevented by the new coronavirus due to vaccinations.

Professor Tim Spector of King’s College London (KCL), head of the study, based on data from the country’s Zoe Covid epidemiological study app, says the results may explain recent infections reported by fully vaccinated people.

“Reduced protection is expected, and this is not a reason for not being vaccinated,” Spector says.

“Vaccines still provide a high level of protection for the majority of the population, especially against the Delta variant, so we still need as many people as possible to fully immunize.”

The expert argues that in the coming winter, protection against infections may drop by up to 50% and that it may be necessary to take booster doses.

The UK is expected to start offering some people a third booster dose of the SARS-CoV-2 vaccine as early as September, but the government has yet to make an official decision.

“Many people may not need this. Many people may have received a natural booster vaccine because they already had a natural Covid infection, so they will essentially be taking three vaccines, ”Spector says.

“Therefore, this problem needs to be dealt with with much more care than simply [a terceira dose] the entire population, which would be a waste and ethically questionable given the resources we have. I think we need a more focused approach than last time, ”he concluded.

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