A study was conducted by ICMR’s Regional Medical Research Centre in Bhubaneswar on 614 fully vaccinated staff, which showed a significant drop in Covid-19 antibodies within four months after vaccination.
Out of 614 candidates, 306 were given both doses of Covaxin and 308 were given both doses of Covishield. 81 people got infected with Covid-19 for the first time, 257 participants were with a previous history of Covid-19 and 33 were re-infected, after being inoculated with both doses of the Covid vaccine.
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Dr Sanghamitra Pati, a co-author of the ICMR study said, “After six months, we should be able to tell you more clearly whether and when a booster would be needed.”
“This does not mean that person is not fully protected. T cells and B cells are also factors that help in creating a memory to fight the virus,” Dr Pati said adding, “A follow-up of this study will be done for a year. These were healthcare workers and more pan India studies are needed for further conclusion.”
Dr Bhattacharya, one of the authors of the study, said that, in Covaxin, antibodies started declining in the second month after vaccination. In Covishield, antibodies started declining after the fourth month of vaccination.
Also Read: From ‘no jab, no job’ to penalties; here’s how nations are making Covid vaccines compulsory“We report a significant decline of antibody post 2 months and 4 months among Covaxin and Covishield recipients after two doses of the Covaxin and Covishield,” she continued.
A similar study was conducted in Britain on more than a million of people, who have been inoculated with both doses of either Pfizer/ BioNTech or AstraZeneca vaccine. The study showed that the vaccine efficacy for Pfizer/ BioNTech reduced by 6 percent after every two months, and the protection was reduced by 10 percent within 4-5 months after taking the AstraZeneca vaccine.