To delay 12 weeks the time between first and second doses of Pfizer’s vaccine increases up to three and a half times antibodies generated against Covid-19. This is the conclusion of a study carried out by researchers at the University of Birmingham, in the United Kingdom, with 175 people between 80 and 99 years old.
The study published this Friday is the first to directly compare the immune responses Pfizer injection if the second dose is given at three weeks, something that Spain does, and at the 12 weeks recommended by the British authorities to give some protection in less time to the most vulnerable people.
“Our study shows that peak antibody responses after the second Pfizer vaccine are markedly improved in older people when this is delayed to 12 weeks,” he said. Helen Parry, study author based at the University of Birmingham.
The work, which has not yet been validated by other experts, found that in those patients who were given the second dose at 12 weeks, antibodies against the virus increased 3.5 times more than in those who had injected the second dose at 3 weeks. However, the study admits that T cells, they do have a higher peak when the second injection is given earlier, in week three.