"Modi govt has admitted that Covaxin consists new born calf serum which is a portion of clotted blood obtained from less than 20 days young cow-calves after slaughtering them…This information should have been made public before," tweeted Pandhi on June 15, 2021.

But official information available in public domain and experts FactChecker spoke to prove that this claim is misleading.

Calf serum not in Covaxin

Covaxin is being manufactured in India by Bharat Biotech and was developed in collaboration with Indian Council of Medical Research-National Institute of Virology, Pune. It falls in the category of inactivated vaccine, in which the pathogen is deactivated so it no longer infects anyone.

The vaccine is developed using Whole-Virion Inactivated Vero Cells derived platform technology. Since it is an inactivated vaccine, it contains dead virus incapable of infecting people but still able to instruct the immune system to mount a defensive reaction against an infection.

The inactivated virus is mixed with adjuvants, substances known to enhance immune response. To grow cells in the lab, certain conditions are needed that allow cells to divide and turn into specific types of cells needed for the experiment. For Covaxin, Dulbecco's Modified Eagle Medium (DMEM), which has several essential nutrients for cell division, is used along with new born calf serum. Cells in multi cellular organisms need certain other growth factors to trigger cell division rather than sole dependence on the nutrients generated by DMEM.

But after the vero cells grow, the serum is removed and then the virus is introduced for viral growth. This results in the destruction of vero cells and that's how the virus is inactivated.

Serum from cow foetuses, also called foetal bovine serum (FBS) was extensively used earlier owing to its rich growth factors, that could increase cell division. But due to ethical issues relating to cruelty on animals, serum from healthy new born calves came up as an alternative.

"Newborn calf serum is usually collected from calves that are about less than 2 weeks old. It has been a standard practice for growing viruses and is not specific to Covaxin. The serum is used as it has very little antibodies that can block virus replication. The presence of foetal bovine serum in Covaxin is unlikely because when the virus is taken all other components are removed. When the vaccine is comes up as the end product, all other components are removed or purified," Dr Gagandeep Kang, a virologist and professor at Christian Medical College, Vellore, told FactChecker.

Virologists say that using cattle blood serum from newborn cattle for vaccines is not a new practice and has been a vital part of biological research. In India, it is imported from other countries. Vaccines for diseases like seasonal influenza, polio, pertussis, rabies and Japanese encephalitis use the same technology to develop inactivated vaccines.

Unlike what Pandhi claimed, the information on how the serum is used for growing vero cells has been in public domain since September 2020, when ICMR and Bharat biotech released a preclinical study on Covaxin. This showed strong immunogenicity and protective efficacy from the trials conducted on hamsters and non-human primates.

"No cows are slaughtered for manufacturing vaccines. These serums are all imported. Nobody uses Indian calf serum since it is not good in quality. A lot of efforts are in place to get a substitute of FBS but it is difficult to procure. Xeno-free medium, which is free of animal products could be a substitute but it is overtly expensive and there is no evidence if it will work. So, Bharat Biotech is not doing anything unethical, they are just following the protocols that have been widely followed and accepted," added Dr Kang.

Dr T Jacob John, a retired virologist, seconded Kang while saying, "Use of FBS is an old technology. Most of it is imported. If at all serum from cow is needed, it can easily be collected from the plasma of a healthy calf without slaughtering them. It is all possible now. One needs to be careful while making such allegations and need not amplify something that is not accurate."

The Centre too issued a clarification on June 16 by saying that although calf serum is involved in the process of making the vaccine and the finished product does not contain the serum. "Newborn Calf Serum is used only for preparation/ growth of vero cells. 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," read the press note issued by the Ministry of Health & Family Welfare.

"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," it added.

Also, Bharatiya Janata Party Spokesperson Sambit Patra clarified this at a media briefing. FBS or serum extracted from new born calves is not present in Covaxin and no mass cow slaughter is being conducted to develop this vaccine, said Patra.

Doctors and experts have also criticised this misrepresentation of facts.

When FactChecker contacted Pandhi for clarification, he replied saying, "It's the government's responsibility to own up its stand mentioned in RTI reply and if the response in the said RTI is misleading than take action against the concerned department/officer."