Coronavirus vaccine: Cocktail of vaccines wrong, blame game will begin

Mixing doses of two Covid-19 vaccines is "very wrong" and this approach towards vaccination will result in a blame game between different vaccine manufacturers if anything goes wrong, said Serum Institute of India Chairperson Cyrus Poonawalla.

The Pune-based institute is the world's largest manufacturer of vaccines by volume.

This comment comes days after the Drugs Controller General of India (DCGI) approved a proposal to conduct a study on mixing Covaxin and Covishield vaccines in India. The study, involving 300 health individuals, will be carried out by Christian Medical College, Vellore.

The purpose of this study is to assess whether a person can be given two different vaccine shots -- one each of Covishield and Covaxin -- to complete the vaccination course.

"There is no need to mix the doses," Cyrus Poonawalla was quoted as saying by The Economic Times. He added that if something goes wrong with this approach, then a blame game would start between manufacturers of the two jabs.

"If anything misfires, Serum will say that the other vaccine is not good and they (the other vaccine company) will blame us claiming there was an issue with our vaccine. I think, it is very wrong to mix the vaccines and you can quote me," the report quoted Cyrus Poonawalla as saying.

In a statement, Cyrus Poonawalla later clarified his stand saying, "To clarify earlier statement: For those who have been administered the first dose of a particular vaccine and in case of the unavailability of the second dose of the same, as an alternative, another vaccine can be administered. That said, the efficacy and the immunogenicity of the combination are dependent on the ongoing studies conducted by regulators."

Recently, the Indian Council of Medical Research (ICMR) too conducted a study on a group of vaccine recipients who were accidentally given doses of different Covid-19 vaccines in Uttar Pradesh earlier this year.

In its study (that is yet to be peer-reviewed), ICMR said mixing doses of Covaxin and Covishield have shown better results in building immunity against the virus causing Covid-19.

The study was conducted between May and June in Uttar Pradesh. As per ICMR, the study suggests that immunisation with combination of an adenovirus vector platform-based vaccine followed by inactivated whole virus vaccine was not only safe but also gave better immunity against variants of coronavirus.