Covid vaccine: Pfizer and AstraZeneca offer high protection 6 months after 2nd dose

Also Read: Indian passport holders do not need prior visa to travel to 60 countries The researchers used records on 1,951,866 (19.5 lakh) and 3,219,349 (32 lakh) adults who had received two doses of Pfizer and AstraZeneca vaccnes, respectively and 2,422,980 (24 lakh) unvaccinated adults. Also Read: Travel insurance policies in demand post pandemic: Survey They found that rates of COVID-19 hospital admission and death were substantially lower among vaccinated than unvaccinated adults up to six months after their second dose.

Vaccine effectiveness against these events was found to be at least 80 per cent for Pfizer, and at least 75 per cent for AstraZeneca vaccine, the researchers said. Also Read: Be ready for new variants as Covid cases rise, warns WHO chief However, waning vaccine effectiveness against infection with SARS-CoV-2 meant that rates in vaccinated individuals were similar to or higher than in unvaccinated individuals by six months after the second dose, they said. "Until now there has been limited and conflicting evidence relating to the rate of waning following second dose of COVID-19 vaccines, whether it extends to severe COVID-19, and whether the rate differs according to age and clinical vulnerability," said Elsie Horne, from the University of Bristol, the study's lead author. "Although we found that protection against severe COVID-19 provided by two doses of vaccine wanes over time, the very high initial protection means that, despite waning, protection remains high six months after the second dose," Horne said.

This finding, the researchers said, was consistent across all adults, including older adults and those who are at risk of severe COVID-19. "We found that the rate at which vaccine effectiveness.