New Delhi, Jun 16 (IANS): Refuting rumour spread by some social media posts, the Central government on Wednesday clarified that Covaxin, India's indigenous Covid-19 vaccine, does not contain newborn calf serum at all.

"There have been some social media posts regarding composition of the Covaxin vaccine where it has been suggested that it contains the newborn calf serum. Facts have been twisted and misrepresented in these posts," said the Ministry.

"Newborn Calf Serum is used only for preparation or growth of vero cells."

Noting that different kinds of bovine and other animal serum are standard enrichment ingredient, and they are used globally for vero cell growth, the Ministry said vero cells are used to establish cell lives which help in production of vaccines.

This technique has been used for decades in Polio, Rabies, and Influenza vaccines.

These vero cells, after the growth, are washed with water, with chemicals (also technically known as buffer), many times to make it free from the newborn calf serum. Thereafter, these vero cells are infected with corona virus for viral growth.

"The vero cells are completely destroyed in the process of viral growth. Thereafter this grown virus is also killed (inactivated) and purified. This killed virus is then used to make the final vaccine, and in the final vaccine formulation no calf serum is used."

Hence, the Ministry said, the final vaccine Covaxin does not contain newborn calf serum at all and the calf serum is not an ingredient of the final vaccine product.

Covaxin is India's first indigenously developed Covid-19 vaccine manufactured by Bharat Biotech. It is being used on adults in India's ongoing Covid-19 vaccination drive since January 16 this year.