Studies from Israel and Qatar and published in the New England Journal of Medicine, support the argument that even fully vaccinated people need to take precautions against infection.
“We conducted this prospective longitudinal cohort study, which included health care workers at Sheba Medical Center, a large tertiary medical center in Israel,” wrote Dr. Gili Regev-Yochay from Sheba and colleagues.
The researchers noted that levels of so-called neutralizing antibodies — the immune system’s first line of defense against infection — are related to protection against infection, but for this study they only studied antibody levels.
“Published work regarding several vaccines, such as those against measles, mumps and rubella, has shown a small reduction of neutralizing antibody levels of 5 to 10% each year,” they wrote. “We found a significant and rapid reduction in the humoral response to the BNT162b2 vaccine within months after vaccination.”
The study also indicated that immunity lasts longer for people vaccinated after natural COVID-19 infection. This is especially strong for people who have recovered from the infection and have been vaccinated again. “Overall, the accumulated evidence from our study and others suggests that the long-term humoral response and vaccine effectiveness in previously infected individuals were superior to those receiving two doses of the vaccine,” they wrote.
Laith Abu-Raddad of Weill Cornell Medicine-Qatar and colleagues wrote, “BNT162B2-induced protection builds up rapidly after the first dose, peaks in the first month after the second dose, and then gradually after.” decreases in months.” “After the fourth month, the decline appears to be accelerating, reaching a low of around 20% in subsequent months,” he added.
Still, the protection against hospitalization and death remained above 90%, he said.
The behavior could be involved in dwindling security, he said. “Vaccinated individuals have higher rates of social interaction than non-vaccinated individuals and may also be less adherent to safety measures,” they wrote. “This behavior may underestimate the vaccine’s real-world effectiveness compared to its biological effectiveness, possibly explaining the lack of protection.”
But it is a sign that countries should be prepared for a new surge of Kovid-19. “These findings suggest that a large proportion of the vaccinated population may lose their protection against infection in the coming months, perhaps increasing the likelihood of new pandemic waves,” they wrote.
Pfizer has argued that immunity from the first two doses of its vaccine begins to decline after a few months. Last month, Pfizer received authorization from the US Food and Drug Administration for booster doses of its vaccine to be approximately six months after people had completed their first two doses.
Israel is ramping up its entire population and now says people will need a third shot to be fully vaccinated.
According to CDC data, in the United States, more than 6 million people have received their third dose of the vaccine and the average rate of booster shots exceeds the rate of people getting vaccinated for the first time.
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