Mix-and-match vaccine highly effective against Covid, says Lancet study

London, October 18

People who received the first dose of the Oxford-AstraZeneca Covid-19 vaccine followed by an mRNA vaccine shot had a lower risk of infection compared to those immunised with both doses of the AstraZeneca, according to a nationwide study in Sweden.

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Since the use of AstraZeneca’s vector-based vaccine against Covid-19 was halted for those below 65 years of age due to safety concerns, all individuals in Sweden who had already received their first dose of this vaccine were recommended an mRNA vaccine as their second dose. “Having received any of the approved vaccines is better compared to no vaccine, and two doses are better than one,” said Peter Nordstrom, a professor at Umea University, Sweden. “However, our study shows a greater risk reduction for people who received an mRNA vaccine after having received the first dose of a vector-based vaccine, as compared to people having received the vector-based vaccine for both doses,” Nordstrom said.

The study, published in The Lancet Regional Health - Europe journal on Monday, is based on nationwide registry data from the Public Health Agency of Sweden, the National Board of Health and Welfare, and Statistics Sweden.

In the main analysis, about 7 lakh individuals were included. During a 2.5-month average follow-up period after the second dose, the study showed a 67 per cent lower risk of infection for the combination of AstraZeneca and Pfizer vaccine shots.

There was a 79% lower risk of infection for AstraZeneca and Moderna vaccine shots, compared to unvaccinated individuals, the researchers said.

For people having received two doses of the AstraZeneca vaccine, known as Covishield in India, the risk reduction was 50%, they said. — PTI

13,596 fresh cases

TOTAL DEATHS 4,52,290

ACTIVE CASES 1,89,694

166 deaths in 24 hours

Survey findings

• 67% lower risk of infection for the combination of AstraZeneca and Pfizer vaccine shots
• 79% lower risk for AstraZeneca and Moderna jabs, compared with unvaccinated individuals
• 50% risk reduction for people having received two doses of the AstraZeneca vaccine (Covishield)

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