India has been combating the COVID-19 pandemic with the weaponry of two indigenous vaccines - Covishield and Covaxin. The country has been going through the third phase of the vaccination drive to vaccinate people between the age group of 18 to 44, which majorly contributes to the nation's total population. The country has so far vaccinated over 24 crore doses of vaccine till Tuesday.
Amid the grounds of the dearth of two vaccines in several states, the Center's new vaccination policy, and the expectation of the influx of the third vaccine, the recent study had compared the efficacy of Covishield and Covaxin and revealed which vaccine produces more antibodies. The study, which was done on the health care workers, had revealed that Covishield produces more antibodies than Covaxin though both the vaccines generate a good immune response.
The pan -India study, which was yet to be released, was posted on the preprint repository MedRxiv on June 4 and it had covered 515 healthcare workers who had received both doses of the vaccines. The study had covered 515 healthcare workers - 305 men and 210 women - from 22 cities in 13 states. In a tweet, Dr. Awadhesh Kumar Singh, lead author of the study and endocrinologist of GD Hospitals in Kolkata, said that both vaccines elicited good immune response after two doses, although seropositivity rates and antibody levels were significantly higher in Covishield compared to Covaxin.
Seropositivity refers to the production of antibodies in an individual and it has been found that Covishield produces more antibodies. The authors of the study had said that among the 515 healthcare workers, 95 per cent showed seropositivity after two doses of both vaccines. Of the 425 Covishield and 90 Covaxin receivers, 98.1 per cent of people who received Covishield showed seropositivity against 80 per cent Covaxin recipients.
According to reports, the study was conducted by researchers from various institutes, including Ahmedabad's Vijayratna Diabetes Center, Kolkata's GD Hospital and Diabetes Institute, Dhanbad's Diabetes and Heart Research Center, Rajasthan Hospital, and Mahatma Gandhi Medical College and Hospital in Jaipur. Besides finding higher seropositivity among Covishield recipients, the study found that the seropositivity rate was significantly more in participants with an age of 60 or less compared to those above 60.
The researchers had also compared the post-vaccination immune responses of all participants with those who had a history of COVID-19, and those who didn't. The study found that participants who had recovered from COVID-19 at least six weeks before the first dose of vaccination and later took both shots were 100 per cent seropositive, and had higher antibody levels compared to others.
While factors such as gender, body mass index, and other comorbidities didn't make any difference, the seropositivity rate of antibodies in people with type 2 diabetes was found to be lower than compared to others. Covishield is manufactured by the Serum Institute of India in Pune while Covaxin is manufactured by the Hyderabad-based Bharat Biotech in collaboration with ICMR and the National Institute of Virology.