India mulls mixing Covishield, Sputnik doses; no recommendation yet

India is considering allowing the mixing of different COVID-19 vaccine doses in what could be the first mix-and-match inoculation. The mix-and-match will notably only be possible for vaccines using similar technologies. For instance, India is considering mixing Covishield and Sputnik vaccines for two-dose inoculations as both are adenovirus-based. Similarly, mRNA-based Pfizer and Moderna jabs could also be mixed. Here are more details.

Decision to be taken after considering scientific evidence: Official

The decision on mixing different vaccines is under consideration by India's COVID-19 working group National Technical Advisory Group on Immunisation (NTAGI). Officials told Mint that the final decision will be taken after considering scientific evidence. NTAGI Chairperson Dr. NK Arora said that the government "would allow mixing and matching of some COVID-19 vaccines," adding, "a formal advisory in this regard will be released soon."

'Purpose only to make vaccinations easier'

However, Dr. Arora maintained that the government continues to encourage using the same vaccine for both doses. "The main purpose of such mix-and-match is only for making vaccination easy," Dr. Arora said, "People who are not getting the second dose of the same vaccine due to reasons ranging from unavailability of the brand to access may go for mix-and-match."

RDIF announced safety results of study on mixing Covishield, Sputnik

Last week, the Russian Direct Investment Fund (RDIF) had released the safety results of a study conducted in Azerbaijan on the safety and immunogenicity of mixed AstraZeneca (Covishield) and Sputnik Light vaccine inoculations. The interim analysis based on 50 volunteers found a high safety profile for the combined use of the vaccines with no serious adverse events.

What does the WHO say on mixing vaccines?

In its interim recommendation last week, the World Health Organization said a combination of recombinant vaccines like Covishield and Sputnik does not require an additional dose of either vaccine. It said immune responses after the first dose of a recombinant jab, followed by an mRNA vaccine, showed higher neutralizing antibody levels and T cell-mediated immune response than two doses of recombinant or mRNA vaccines.

India's COVID-19 expert panel recommended mixing Covishield, COVAXIN

Last week, the Subject Expert Committee (SEC) on COVID-19 of the Central Drugs Standard Control Organization (CDSCO) had reportedly recommended conducting clinical trials on mixing and matching of Covishield and COVAXIN doses. It also recommended that the Christian Medical College (CMC), Vellore, be permitted to conduct trials for the same. Notably, COVAXIN (whole-virion inactivated vaccine) and Covishield (adenovirus vaccine) have two different vaccine platforms.

What do experts say?

The mix-and-match vaccination strategy is known as heterologous prime-boost immunization and has been reportedly used against diseases such as Ebola and AIDS in the past. However, experts are divided over its applicability for COVID-19. Many believe inoculating two different vaccine doses would produce a strong immune response against the virus. Others, however, argue it would not be effective as the vaccines are designed differently.

No recommendation on mixing vaccines so far: Government tells Parliament

The Health Ministry clarified in the Rajya Sabha on Tuesday that no such formal recommendation had been made so far. Scientific evidence is still evolving on the subject, Minister of State for Health Bharati Pravin Pawar said in a written reply.