Higher immunity after vaccine doses: Study | Economic Times

A new study bolsters the view that Covid-19 vaccines Covishield and Covaxin produce high immune response after two doses.In examining the immune response to the two vaccines in 515 Indian healthcare workers, researchers, however, found that Covishield may have a greater ability to produce more antibodies and higher seropositivity rate. Also, both vaccines showed good and similar immune response even after a single dose in people who had contracted Covid-19. Oxford-AstraZeneca vaccine Covishield is being produced by Serum Institute of India (SII), while Covaxin is manufactured by Bharat Biotech. “This suggests that both vaccines work well and we could produce some real-world evidence to show that Covaxin induces good protective antibodies after two doses in the absence of published phase-3 data at the moment,” said AK Singh, lead author of the research paper. “Covishield has already published phase-3 data.”83291296Singh is a senior consultant endocrinologist at GD Hospital and Diabetes Institute, Kolkata. The paper has come in the preprint server of MedRxiv and has been acknowledged by British Medical Journal and Yale University. “Among 515 healthcare workers (305 male, 210 female), 95% showed seropositivity (higher antibodies) after two doses of both vaccines,” the paper said. “Of the 425 Covishield and 90 Covaxin recipients, 98.1% and 80%, respectively, showed seropositivity. However, both seropositivity rate and average rise in anti-spike antibody were significantly higher in Covishield versus Covaxin recipients.”The experts did not observe any difference in relation to gender, body mass index, blood group and any comorbidity. People aged 60 years and above or those with type-2 diabetes had a significantly lower seropositivity rate, indicating a comparatively lower antibody response. India, which started its vaccination drive in January, has so far administered one vaccine dose to 43% of its 60-plus population. On the other hand, 37% of the 45-plus group have received at least one dose. The researchers did not find any difference in the breakthrough infections. The study is ongoing and experts are looking at the data to find out what’s going on in antibody titre in both SARS-CoV-2 naïve and recovered individuals.This is the first study that compares antibody response to Covishield and Covaxin and demonstrates the need for two doses to have a significant antibody response.