Covishield produced more antibodies than Covaxin, finds preliminary study

New Delhi: Covishield vaccine produced more antibodies than Covaxin, according to the Coronavirus Vaccine-induced Antibody Titre ( COVAT) preliminary study involving healthcare workers (HCW) who have received both doses of either of the two vaccines. Seropositivity rates to anti-spike antibodies were significantly higher in Covishield recipients compared to Covaxin after the first dose, the study claimed. The study is a preprint and has not been peer-reviewed, so should not be used to guide clinical practice. It said that both vaccines – Covishield and Covaxin – elicited a good response after two doses, but seropositivity rate and median anti-spike antibody were significantly higher in Covishield. “Amongst the 552 HCW (325 Male, 227 Female), 456 and 96 received the first dose of Covishield and Covaxin respectively. Overall, 79.3 percent 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 percent; 61.5 vs. 6 AU/ml; both p<0.001),” the study said. The study involved those healthcare workers who have been administered either of the two vaccines Covishield and Covaxin and are with or without past history of SARS-CoV-2 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-time points between 21 days or more after the first dose to 6 months after the second dose,” the study said. However, the conclusion of the study said that both the vaccines have shown elicited good immune response. “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,” it said.