Covishield vaccine produces more antibodies than Covaxin, according to a study carried out on Indian health care workers (HCW), who have received both the doses of either of the two vaccines.
As per the preprint version of the Coronavirus Vaccine-induced Antibody Titre (COVAT) study, antibody response (seropositivity rate and median [inter-quartile range, IQR) antibody titre) was significantly higher in Covishield as compared to Covaxin.
The study was carried out by eminent medical professionals from Kolkata, Jaipur, Ahmedabad and Jharkhand.
Among the 515 HCW including 305 male and 210 female, 95.0% showed seropositivity after two doses of both the Covid19 vaccines. Of the 425 recipients of Covishield and 90 recipients of Covaxin, 98.1% and 80.0% respectively, showed seropositivity, the study said.
However, both the seropositivity rate and median (IQR) increase in the anti-spike antibody was significantly higher in the Covishield versus Covaxin recipients (98.1 versus 80.0%; 127.0 versus 53 AU/mL; both p<0.001), the study added.
According to the study, both vaccines elicited good immune response after two doses, although seropositivity rates and median anti-spike antibody titre was significantly higher in Covishield compared to Covaxin arm.
The COVAT study is an ongoing, pan-India, cross-sectional study that was approved by the ethical committee of Thakershy Charitable Trust in Ahmedabad.
“To the best of our knowledge, this Pan-India cross-sectional COVAT study would be the first of its kind that has involved HCW from 13 States and 22 cities and reporting anti-spike antibody kinetics after two completed doses of two different vaccines,” the study said.
As per the study, combined results of both the Covid19 vaccines showed 95% seropositivity to anti-spike
antibody, 21-36 days after the second completed dose.
Gender, presence of comorbidities and the type of vaccine received were independent predictors of antibody response after the second dose, the study observed.