Mixed Covishield, Covxin doses produce better protection: ICMR

Mixed Covishield, Covxin doses produce better protection: ICMR

Mixed Covishield, Covxin doses produce better protection: ICMR

New Delhi  : The Indian Council of Medical Research (ICMR) today said a mixed Covid immunisation routine, with a dose of Covishield followed by one of Covaxin, was safe and elicited a better immune response than the regime where uniform two doses of any of the two vaccines were administered.

Effective against Alpha, Beta, Delta

ICMR study followed 18 UP residents who inadvertently received mixed doses

Mixing found effective against variants of concern Alpha, Beta and Delta

Authors say a larger trial needed to further corroborate the findings

An earlier study found similar findings in a mouse model

“The immunisation with a heterologous combination of an adenovirus vector platform-based vaccine (Covishield) followed by an inactivated whole virus vaccine (Covaxin) is safe and elicits better immunogenicity than two doses of homologous vaccination using the same vaccines,” said the study, published as a pre-print but yet to be peer-reviewed.

Led by ICMR scientist Rajni Kant, the study said the findings had an important implication for the Covid-19 vaccination programme wherein heterologous immunisation would pave the way for induction of improved and better protection against the variant strains of SARS-CoV-2.

“Such mixed regimens will also help to overcome the challenges of shortfall of particular vaccines and remove hesitancy around vaccines in people’s mind that could Mixed Covishield, Covaxin doses...

have genesis in programmatic ‘errors’, especially in settings where multiple Covid-19 vaccines are being used. However, to conclusively prove these findings, a multicentre random clinical trial needs to be carried out,” say study authors at a time when the WHO is yet to issue guidance on mixing of vaccine doses. The study, titled ‘Serendipitous Covid-19 Vaccine-Mix in Uttar Pradesh, India: Safety and Immunogenicity Assessment of a Heterologous Regime’, also found that no major systemic adverse events were reported and reactogenicity profile of the participants of heterologous group (mixed vaccine) was comparable to homologous groups.

“Despite the high median age of the participants of the heterologous group (62 years) which got mixed vaccine in our study, the reactogenicity profile demonstrated that mixing of the two vaccines based on different platforms is safe,” the study shows.

The study followed 18 Uttar Pradesh residents who inadvertently received mixed doses when the inoculation plan was expanded and 40 recipients each of Covishield and Covaxin. The study authors say the sample size of 18 participants was small and, therefore, a larger trial was needed to further corroborate the findings of the current study. The authors said theirs was the first report of heterologous (mixed vaccines) immunisation with an adenovirus vector-based and an inactivated whole virion vaccine in humans demonstrating safety and significantly improved immunogenicity.