Administering two different COVID-19 vaccines under research, supply constraints should be resolved, say experts

Administering two different COVID-19 vaccines, specially those with similar underlying platform, is still under research and supply constraints have to be resolved so that people can take their vaccine doses on time, experts have said.

A "vaccine goof up" was recently reported from Siddharthnagar in Uttar Pradesh in which some people were given Covishield in the first dose and Covaxin in the other.

Experts said that of such goof up having happened at a few other places cannot be ruled out.

An investigation is taking place over the incident in Siddharthnagar and officials have said it is a case of negligence.

Dr Rajib Dasgupta, chairperson of the Centre of Social Medicine and Community Health at Jawaharlal Nehru University, said that mixing of vaccines or a combination of vaccines and is currently under study now.

"The combination of vaccines is still under investigation and research. The potential mixing of what we call a homologous boost ...homologous combination boost are vaccines that have similar mechanisms or similar platforms. Only one or two initial results are available from the trials across the world but those are interim results and not final results," he said.

"There is a supply problem all across the world at present. The mixing of vaccines is not authorised in India and certainly not Covaxin or Covishield," added Dr Dasgupta, who is also a member of the national committee that tracks adverse events following immunization.

Delhi government is expected to receive around 91,960 doses of Covaxin in June which will only be available for those who have taken their first dose.

Dr VK Paul, NITI Aayog member (Health) had said that as per protocol, the vaccination centres should stick to the same dose of vaccines, but if a mix-up has happened, "there are unlikely to be any adverse effects."

"On mixing of Covishield and Covaxin we do not have any studies in India, but some countries are doing research," he added.

According to the central government's vaccination protocol, the interval between first and second doses of Covaxin, manufactured by Bharat Biotech, should be at least four weeks and that for Covishield, manufactured by Serum Institute of India, should be at least 12 weeks.

( With inputs from ANI )