NEW DELHI :
A senior expert at the All India Institute of Medical Sciences (AIIMS) has come out against the government policy of mixing covid-19 vaccine doses, warning that in case of an adverse event it will be very difficult to establish which vaccine caused it.
Mint reported on Tuesday about government plans to open up covid-19 booster doses to all adults, marking a dramatic scale-up in the vaccine’s rollout that will make tens of millions more eligible to receive the precautionary jabs.
Mixing and matching will lead to no accountability of pharmaceutical companies in case of any adverse effect, said Sanjay Rai, professor of community medicine at AIIMS.
He called for more scientific studies to establish the efficacy and safety of mix-matched vaccines.
Globally, 33 vaccines have been approved for mix-match doses. In India, Christian Medical College (CMC) Vellore is conducting a trial on mixing of two covid-19 vaccines—Covaxin and Covishield.
Under the current vaccine mixing protocol, someone who is fully vaccinated with vaccine ‘A’ receives a booster dose of vaccine ‘B’, and vice versa.
“At this point of time, mixing of vaccines is completely irrational. As of now, there is no dearth of vaccines and no emergency situation in the country. We are using covid-19 vaccine for the first time, and to mix two drugs we need to have long-term scientific evidence. If [mix and match] happens now, there will be no accountability of the pharma companies if any adverse effect occurs to an individual,” said Dr Rai.
“For example, previously there was a thalidomide drug that was being prescribed to women during pregnancy to control vomiting. After many years, research showed that this particular drug used to cause malformation of limbs in a newborn. As a result, thalidomide use during pregnancy was banned. This is just one example. If we say that mixing of vaccines increases the antibodies in the body, it does not mean it has high protection level. We have to see that mixing of vaccines should have neutralizing antibodies to neutralize the virus. And hence, long-term scientific evidence is required for such kind of mixing of vaccine doses,” Dr Rai said.
A neutralizing antibody is one that defends a cell from a pathogen or infectious particle by neutralizing any effect it has biologically.
Queries emailed to spokespersons of Bharat Biotech, Serum Institute of India, AIIMS and Union ministry of health and family welfare on Tuesday remained unanswered at press time. A spokesperson for CMC Vellore did not respond to phone calls or to a text message.
At present, the government has authorized giving booster doses to everyone above the age of 60 years, healthcare workers and front line workers.
According to the health ministry, as of Tuesday, nearly 22 million eligible individuals have received a booster dose.