Even As WHO Calls Mix And Match Dangerous, DCGI Clears Study On Mixing Covaxin And Covishield

Days after a study involving limited participants in the country found that administering people a dose of Covishield, followed by Covaxin in the second dose is safe and improves immunity, the Drugs Controller General Of India (DCGI) has cleared it for its clinical trials.

The DCGI study will be conducted by Christian Medical College, Vellore in Tamil Nadu.

AFP

"Permission has been granted for a research study by CMC Vellore (Tamil Nadu) on mixing of vaccines doses," Dr VK Paul, NITI Aayog Member (Health), said on Tuesday.

A Subject Expert Committee of the Central Drugs Standard Control Organisation (CDSCO) had recommended conducting the study on July 29.

ICMR Study

Last week, the Indian Council of Medical Research (ICMR) had said that mixing of Covishield and Covaxin is safe and improves immunity.

The conclusion was based on studying 18 people from Audai Kalan village of Siddharthnagar district of eastern Uttar Pradesh, who had received Covishield as the first dose but were inadvertently administered Covaxin in the second dose after an interval of six weeks.

Covishield, developed by University of Oxford-Astrazeneca, is a viral vector vaccine that uses an adenovirus found in Chimpanzees, to deliver spike proteins and mount a tolerable immune response in response to a live virus, Covaxin, developed by the Hyderabad-based Bharat Biotech uses a similar inactive viral strain.

PTI

The regime for both the vaccines initially included a second homologous booster dose following a priming dose at an interval of 4 weeks. With gradually emerging evidence, the gap between the two doses of Covishield was increased to 6-8 weeks and later to 12 weeks.

"The findings suggest that immunisation with a combination of an adenovirus vector platform-based vaccine followed by an inactivated whole virus vaccine was not only safe but also elicited better immunogenicity," revealed the study led by Pune-based National Institute of Virology (NIV).

The results showed that the people in the mix and match group had superior immunogenicity profiles against Alpha, Beta and Delta variants of Covid-19. The IgG antibody and neutralising antibody response of the participants was also significantly higher compared to other groups, the ICMR said.

BCCL

The study reported no major adverse events. "The findings have an important implication for the Covid-19 vaccination programme wherein heterologous immunisation will pave the way for induction of improved and better protection against the variant strains of SARS-CoV-2," the ICMR said

"Such mixed regimens will also help to overcome the challenges of the shortfall of particular vaccines and remove hesitancy around vaccines in people's mind that could have genesis in programmatic 'errors', especially in settings where multiple Covid-19 vaccines are being used," added the apex medical body.

Around the world, too scientists have been exploring similar options.

Studies around the world

In May, preliminary results from the first trial in Spain involving more than 600 people show the benefits of combining different coronavirus vaccines had shown that vaccinating people with both the Oxford¨CAstraZeneca and Pfizer¨CBioNTech COVID-19 vaccines produces a potent immune response against the virus.

Several European countries including the UK have been seriously considering mixing Pfizer and Moderna vaccine shots as both are mRNA-based.

Others are mixing AstraZeneca and Pfizer vaccines as both produce different kinds of immune responses.

In the UK, there is also a proposal for mix and match when it comes to the third, booster dose. This means that if someone has received the two doses of the COVID-19 vaccine, they will be administered a different jab as the booster dose.

Not yet, says WHO

But the World Health Organization (WHO) has expressed caution and even called it dangerous.

"Really want to caution folks, because there is a tendency now for people in countries which enough availability of vaccines to voluntarily start thinking." WHO chief scientist Soumya Swaminathan had recently said.

"So it's a little bit of a dangerous trend here where we're in a data-free evidence-free zone as far as a mix and match there is limited data on mix and match. There are studies going on, we need to wait for that," she added.