A recent study has revealed that healthcare workers in India who were administered Covishield have shown better antibody response than the ones who had received the Covaxin shots. The study, published in an online archive for unpublished manuscripts in medical sciences medRxiv, has not been peer-reviewed yet.

The study by Dr AK Singh and his colleagues was aimed at analysing the antibody response after two complete doses of Covishield and Covaxin, and the doctors have concluded that while both Covishield and Covaxin elicited a good immune response after two doses, the seropositivity rates were significantly higher in Astra Zeneca's Covishield as compared to Bharat Biotech's Covaxin. The anti-spike antibody titre was found to be much higher in Covishield recipients compared to Covaxin as well.

"Amongst the 552 HCW (325 Male, 227 Female), 456 and 96 received the first dose of Covishield and Covaxin respectively. Overall, 79.3 per cent showed seropositivity after the first dose. Responder rate and median (IQR) rise in anti-spike antibody were significantly higher in Covishield vs Covaxin recipient (86.8 vs. 43.8 per cent; 61.5 vs 6 AU/ml; both p<0.001)," the study revealed.

The healthcare workers who were involved in the study have been administered either of the two Indian approved vaccines, Covishield and Covaxin, and are with or without past history of the Covid-19 infection. "This ongoing, Pan-India, Cross-sectional, Coronavirus Vaccine-induced Antibody Titre (COVAT) study is being conducted amongst HCW, with or without past history of SARS-CoV-2 infection. SARS-CoV-2 anti-spike binding antibody is being assessed quantitatively at four timepoints between 21 days or more after the first dose to 6 months after the second dose," the study said.

Concluding that both Covishield as well as Covaxin have elicited good immune response in the recipients, the study added, "While both vaccines elicited immune response, seropositivity rates to anti-spike antibody were significantly higher in Covishield recipient compared to Covaxin after the first dose. Ongoing COVAT study will further enlighten the immune response between two vaccines after the second dose."