Covishield Produces More Antibodies Than Covaxin: Latest Study

Ever since the vaccination drive began in India, many of us were perplexed over choosing between Covaxin and Covishield. Compiling information from various sources were common sights among us. But the latest study suggests that the Indian health care workers who were administered Covishield have shown better antibody response than the Covaxin recipients, giving a slight clarity to our unanswered questions.

The study for unpublished manuscripts in medical sciences medRxiv showed that after taking two shots of the vaccines, 98 per cent recipients of Covishield showed antibody response, while in Covaxin receipts was 80 per cent. This study has been published by a group of doctors – Awadhesh Kumar Singh, Sanjeev Ratnakar Phatak, Ritu Singh, Kingshuk Bhattacharjee, Nagendra Kumar Singh, Arvind Gupta, and Arvind Sharma. However, they are yet to peer-review as there was no competing interest and funding.

“We assessed the humoral immune response after the completion of two doses of both ChAdOx1-nCOV (Covishield) and BBV-152 (Covaxin) vaccines in Indian health care workers,” the authors said. The study further added that there were fewer “breakthrough infections” after the Covaxin shots. This means, a patient testing positive for the coronavirus two weeks after receiving the second shot of Covaxin.

A total of 515 healthcare workers from 22 cities were surveyed between January and May. Among 515, 90 received Covaxin shots. One dose of Covishield produced 10 times more antibodies than Covaxin. After a second dose was added, it was found that two shots of Covishield produced about six times more antibodies than Covaxin. Of the 425 Covishield recipients, 98.1 per cent showed seropositivity, and of the 90 Covaxin recipients, 80 per cent showed seropositivity. (seropositivity=having antibodies in blood serum).

The co-developer of covaxin, Samiran Panda, head of epidemiology and communicable division at the Indian Council of Medical Research, said that antibody developed or not developed is a binary variable (above a predefined laboratory cut-off). One needs to examine the result from a quantitative comparison, the difference between the mean or median titre between the two groups. “Any arbitrary draw of a sample brings in a bias and does not allow extrapolation of inference on a larger universe of people,” said Panda.

On Sunday, India reported 1,14,460 new coronavirus infections in 24 hours, while the deaths rose by 2,677. This was the lowest daily count in two months.