A latest study has found that both vaccines, Covishield and Covaxin elicited good immune response after two doses, although seropositivity rates and the median anti-spike antibody titre was significantly higher in Covishield as compared to Covaxin.

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The study is titled, Antibody Response after Second-Dose of ChAdOx1-nCOV (CovishieldTM) and BBV-152 (CovaxinTM) among Health Care Workers in India: Final Results of Cross-sectional Coronavirus Vaccine-induced Antibody Titre (COVAT) study published MedRxiv. The results found that among the 515 HCW (305 Male, 210 Female), 95.0 per cent showed seropositivity after two doses of both vaccines.

Of the 425 Covishield and 90 Covaxin recipients, 98.1 per cent and 80.0 per cent respectively, showed seropositivity. However, both seropositivity rate and median (IQR) rise in anti-spike antibody were significantly higher in Covishield vs. Covaxin recipient (98.1 vs. 80.0 per cent; 127.0 vs. 53 AU/mL; both p<0.001), the study said. This difference persisted in 457 SARS-CoV-2 naive cohorts and propensity-matched (age, sex and BMI) analysis of 116 cohorts. While no difference was observed in relation to sex, BMI, blood group and any comorbidities; people with age more than 60 years or those with type 2 diabetes had a significantly lower seropositivity rate.

Both vaccine recipients had similar solicited mild to moderate adverse events and none had severe or unsolicited side effects. In SARS-CoV-2 naive cohorts, sex, presence of comorbidities, and vaccine type were independent predictors of antibody positivity rate in multiple logistic regression analysis. "Both vaccines elicited good immune response after two doses, although seropositivity rates and the median anti-spike antibody titre was significantly higher in Covishield compared to Covaxin arm", the study said.

A pan-India, cross-sectional, Coronavirus Vaccine-induced Antibody Titre (COVAT) study was conducted that measured SARS-CoV-2 anti-spike binding antibody quantitatively, 21 days or more after the first and second dose of two vaccines in both severe acute respiratory syndrome (SARS-CoV-2) naive and recovered HCW. The primary aim was to analyse antibody response (seropositivity rate and median [inter-quartile range, IQR] antibody titre) following each dose of both vaccines and its correlation to age, sex, blood group, body mass index (BMI) and comorbidities.