The government on March 3 said that any decision on the mixing and matching of a booster dose of COVID-19 vaccines will be taken based on science.

Addressing a press conference here, NITI Aayog Member (Health) V K Paul said studies are going on regarding the mixing and matching of booster doses of COVID-19 vaccines and they are being "constantly reviewed". "As per the new information and science and knowledge, a decision would be guided on (by) that," he said.

On the Corbevax vaccine, Paul said it will find a way into the national vaccination programme as an order has been placed and delivered for a certain quantity. A decision on how and when to use it will be based on scientific considerations. "As the emergency use authorisation (for Corbevax) has been given for the general adult population and also for children, be rest assured that the data has been seen by the drug regulator (before giving the nod).

"We have placed the order for a certain quantum which has been delivered. This vaccine will find a way into the national programme but how best to use it and when to use it, these decisions will follow based on scientific considerations and the overall approach of our vaccination programme which focuses on a systematic approach starting with the neediest and high prioritised groups," Paul said.

The Corbevax vaccine is administered through an intramuscular route with two doses scheduled 28 days apart. It is stored at 2 to 8 degrees Celsius and presented as 0.5 ml (single dose) and 5 ml (10 doses) vial pack. Responding to a query on whether COVID-19 vaccination will be an annual affair, Director General of Indian Council for Medical Research Balram Bhargava said the jury is out on that.

"We have seen that for influenza, a yearly vaccination has been found to be useful. It is being practised for high-risk groups in India. We don't know whether this disease has become endemic or is becoming endemic. Once that happens, we will be in a better position to answer," he said.