Covid-19: Good immune response from Covishield and Covaxin, finds study

MUMBAI/HYDERABAD: A ‘real-world’ study of vaccinated healthcare workers has found Covishield and Covaxin could produce a high immune response in up to 95% recipients and prevent serious disease in those infected after immunisation. Interestingly, the Oxford vaccine Covishield could generate antibodies in more individuals compared to Bharat Biotech’s Covaxin, a pre-print of the first such Indian study has stated. Most vaccine efficacy studies so far have been lab-based.
The pan-India study of 515 vaccinated healthcare workers — 425 with Covishield and 90 with Covaxin — from 13 states and 22 cities found the vaccines could generate an immune response in 95% recipients 21-36 days after the second dose.




Seropositivity was observed in 98% of those immunised with Covishield as opposed to 80% Covaxin recipients, a finding the researchers called “surprising”.
Even the anti-spike antibody titre was found to be significantly higher in Covishield recipients (115 AU/ml) compared to Covaxin (51 AU/ml).
While factors such as gender, BMI and other comorbidities didn’t seem to play much of a role, the seropositivity rate or antibodies in people above 60 years or those with type 2 diabetes was found to be significantly lower.




Seropositivity rate was significantly more in participants with age less than 60 years (96.3% seropositivity) as against 87.2% in the 60-plus bracket. Infection post vaccination was seen in 5% of the study group, but none suffered from severe Covid-19.
Lead author and endocrinologist Dr Awadhesh Kumar Singh of G D Hospital & Diabetes Institute, Kolkata, said the study was not to comment on which one is a better vaccine, but to look at the real-world effectiveness of vaccination.




In the absence of measuring neutralising antibody and cell mediated response, it is difficult to comment whether one is superior,” he said. Results of the Cross-sectional Coronavirus Vaccine-induced Antibody Titre (COVAT) study were published in pre-print server MedRxiv on June 4.
“In individuals who have had Covid infection, both vaccines are equally good and could produce high antibodies even after a single shot. But for those who haven’t got Covid, Covishield could provide an edge,” he said