ICMR study reveals how single Covaxin jab can be equivalent to two doses for special cases

A single dose of Covaxin for previously COVID-19 infected individuals is equivalent to two doses of the vaccine in infection-naive individuals, suggests the pilot study of the Indian Council of Medical Research (ICMR).

ICMR scientists conducted pilot research to ascertain the antibody responses to the BBV152 vaccine in individuals previously infected with SARS-CoV-2.

In the study, blood samples were collected from 114 healthcare professionals and frontline workers who received the BBV152 vaccine (Covaxin) from February to May 2021. Prior infection with SARS-CoV-2 was determined at baseline. Serum samples were used to estimate SARS-CoV-2 nucleoprotein-specific IgG, spike protein-specific IgG, and neutralizing antibodies (NAb).

In the results, it was observed that participants with previous SARS-CoV-2 infection after a single vaccine dose elicited IgG (N) and IgG (S) antibody levels along with NAb binding inhibition responses levels similar to infection-naive vaccinated participants who had taken two doses of the vaccine.

"In conclusion, almost all participants with prior COVID-19 infection, except two, had detectable antibodies at the time of vaccination. This study offers evidence in support of public health-oriented and immunologically sustained vaccine strategies. If our preliminary findings are confirmed in large population studies, a single dose of BBV152 vaccine may be recommended to previously confirmed SARS-CoV-2 infected individuals so that the naive individuals could attain the larger benefit of a limited vaccine supply," reads the pilot study of ICMR.