Bhubaneswar: The antibodies produced among the recipients of Covaxin starts to decline after two months while those who have been vaccinated with Covishield vaccine take three months for the same, said a recent study by ICMR-regional medical research centre (RMRC), Bhubaneswar.
Reportedly, the samples were collected from 614 patients for the study by RMRC. Among them, 308 were Covishield recipients and the rest 306 received Covaxin jabs. A total of 81 breakthrough cases were recorded among participants for whom infection post-vaccination acted as a booster.
The study that commenced in March 2021 was undertaken to determine IgG (Immunoglobulin G, the most common antibody) antibody among health care workers with completed dose of either Covaxin or Covishield. They were followed for 24 weeks after first dose of either vaccine to record the periodic changes in titre, concentration, clinical growth and persistence of vaccine-induced SARS-CoV-2 antibodies.
It was found that the production of vaccine-induced IgG antibodies is significantly higher in Covishield compared to Covaxin. In sero-negative individuals, the rate of sero-conversion after 28 days after the first dose was 81.9% for Covishield and 16.1% for Covaxin, added reports.
In eight weeks, antibodies were found to be declining. This will be followed up after six months and that there are plans to continue this over a period of time, said ICMR-RMRC, Bhubaneswar, Director Sanghamitra Pati.
“Then only can we say whether a booster is required or not and if required, when,” added Pati.
