Decline in antibodies levels within four months of getting Covishield jab, duration even lesser for Covaxin: ICMR
An ICMR study reveals that those fully vaccinated with Covaxin show a drop in antibody levels within two months while those who have received both the doses of Covishield report a similar drop in four months.
A majority of the Indian population has been vaccinated with Covishield. Photo: WHO
A study conducted by the Indian Council of Medical Research (ICMR), has found a significant drop in the levels of antibodies amongst the individuals vaccinated with Covishield and Covaxin COVID19 vaccines.
The study found that the levels of antibodies began to drop after four months of receiving both the doses of Covishield and two months after being fully vaccinated by Covaxin.
The study was conducted on 614 fully vaccinated health workers at ICMR’s Regional Medical Research Centre in Bhubaneswar, Odisha. Of the total participants, 308 participants were given two doses of the Covishield vaccine and 306 were given two doses of Covaxin.
“In Covaxin, antibodies started declining in the second month after vaccination. In Covishield, antibodies started declining after the fourth month of vaccination,” ICMR-RMRC scientist Devdutta Bhattacharya, one of the authors of the study, was quoted as saying.
“But this does not mean that person is not fully protected,” the scientist assured.
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The study which commenced in March this year was undertaken to determine the most common antibody IgG (Immunoglobulin G) among fully-vaccinated healthcare workers in Odisha.
According to the study, the production of vaccine-induced IgG antibodies is significantly higher in Covishield compared to Covaxin. In seronegative individuals, the rate of seroconversion after 28 days of the first dose was 81.9 per cent for Covishield and 16.1 per cent for Covaxin, the study noted.
Meanwhile, more than 800 million vaccine doses have been administered in the country. A majority of the Indian population has been vaccinated with Covishield. Of the total doses, 88 per cent were of Serum Institute’s Covishield and 11 per cent of Bharat Biotech’s Covaxin. Besides Covishield and Covaxin, India is also administering Sputnik V vaccine doses.