New Delhi: The Covishield vaccine produces more antibodies than Covaxin though both generate a good immune response, says a pan-India study of healthcare workers who had received both doses of the preventives.
The yet-to-be-published study, posted on the preprint repository MedRxiv on June 4, covered 515 healthcare workers (HCW) — 305 men and 210 women — from 22 cities in 13 states.
Covishield, from the Oxford-AstraZeneca stable, is manufactured by the Serum Institute of India in Pune. Covaxin is the indigenously manufactured vaccine by Hyderabad-based Bharat Biotech in collaboration with ICMR and the National Institute of Virology (NIV).
The blood samples of those participating in the study were tested for the quantity of antibodies produced and levels of specific antibodies that are directed to the spike protein of the virus, which is regarded as a proxy for protection.
Both vaccines elicited good immune response after two doses, although seropositivity rates and antibody levels were significantly higher in Covishield compared to Covaxin, Awadhesh Kumar Singh, lead author of the study and consultant endocrinologist, G D Hospital and Diabetes Institute, Kolkata, said in a tweet.
Seropositivity was observed in a higher number of people vaccinated with Covishield as compared to those immunised with Covaxin.
Among the 515 HCW, 95 per cent showed seropositivity after two doses of both vaccines. Of the 425 Covishield and 90 Covaxin recipients, 98.1 per cent and 80 per cent respectively, showed seropositivity, said the study authors.
Seropositivity refers to the production of antibodies in an individual.
The study was conducted by researchers from various institutes, including Ahmedabad's Vijayratna Diabetes Centre, Kolkata's G D Hospital and Diabetes Institute, Dhanbad's Diabetes and Heart Research Centre and the Rajasthan Hospital and Mahatma Gandhi Medical College and Hospital in Jaipur.