The data, published Monday in The Lancet medical journal, said that analysis of the vaccine’s effectiveness data in preventing symptoms requiring hospitalization, or death from Covid-19, showed that it persists by 90 percent effective for at least six months, even in the face of a fast delta mutant. diffusion.
Researchers said that the reason was the decline in its effectiveness over time and not to confront strains more capable of spreading the virus.
The data show that the effectiveness of the vaccine against the delta mutant was 93 percent after the first month and then decreased to 53 percent after four months. In the face of other mutations of the Corona virus, the effectiveness decreased to 67 percent from 97 percent.
The US Food and Drug Administration has approved a booster dose of the Pfizer/Biontech vaccine for older adults and some Americans at high risk of infection. Scientists demanded more data before recommending that booster doses be given to everyone who received the vaccine.
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