The Indian Government might allow the Primary Covid-19 vaccine as a Covid booster. According to a study conducted at Christian Medical College (CMC) Vellore, mixing the two major vaccines - Covishield and Covaxin did not result in a significant encouraging conclusion on the other hand the booster dose with the same vaccine as the primary Covid-19 vaccine enhanced immunity well. Hence experts suggest that it was safer to move on with the vaccination drives and administer the same vaccine as a booster or precautionary dose as the first two doses instead of mixing up. 

The National Technical Advisory Group on Immunization (NTAGI) reviewed the studys findings at a meeting last week. CMC will send trial data to the Drug Controller General of India (DCGI), who will decide what the booster dose should be. Currently, it was difficult to state whether a heterologous (mix and match) or homologous (same vaccine) regime is superior.

India has initiated administering the booster or precaution dose with the same vaccine as the primary doses and no mixing as permitted to date. 

The mix and match approach is still not understood well, hence researchers throughout the world are investigating if combining two different Covid-19 vaccines can result in better and longer-lasting immunity to the virus. (ET Healthworld, May 11, 2022)