Covaxin provides protection against the Delta (B.1.617.2) and the Beta (B.1.351) variants of COVID-19, finds an ongoing study being conducted by the National Institute of Virology-Indian Council of Medical Research (ICMR) and Bharat Biotech.
The study, however, has also found that the vaccine produces lesser antibodies against the two variants as compared to the original strain.
The Delta variant was first identified in India and is the dominant strain in the country. It is thought to be behind the devastation caused by the second wave. The Beta variant, on the other hand, was first found in South Africa.
The study is in the preprint stage and has not been peer reviewed yet.
The small study compared the blood samples of 20 participants who recovered from COVID with that of 17 participants who were vaccinated with Covaxin, to check their immune response to the Delta and Beta variants of COVID-19.
The results found that Covaxin recipients had a 3.0 and 2.7-fold reduction in neutralisation titers (antibody production) against the Beta and Delta variants respectively, as compared to the 3.3 fold and 4.6-fold reduction in neutralisation titers witnessed in COVID recovered participants.
What this means is that, although the vaccine produced lesser antibodies against the variants as compared to the original strain, it is still higher than those produced by COVID recovered patients.
"Although, there is reduction in neutralisation titer, the whole-virion inactivated SARS-CoV-2 vaccine (BBV152) demonstrates protective response against VOC B.1351 and B.1.617.2," says the study.
Other Vaccines vs the Delta Variant
Previous studies have also pointed to a reduced efficacy of the COVID vaccines against the Delta variant.
Earlier this month, another preprint study in India found that Covishield produced more antibodies than Covaxin, though both provide "a good immune response."
“Of the 425 Covishield and 90 Covaxin recipients, 98.1 percent and 80.0 percent, respectively, showed seropositivity.”Preprint study led by Dr Awadhesh Kumar Singh, consultant endocrinologist, GD Hospital and Diabetes Institute, Kolkata, West Bengal
A recent study conducted by the UK's government body, Public Health England (PHE), points to the AstraZeneca (Covishield in India) and Pfizer vaccines, being less effective against the Delta variant as compared to the B.1.1.7 variant, first found in Britain.
The difference was particularly sharp after the first dose which provided 33 percent less protection against the former, making the case for shorter gaps between the two vaccine doses.
Another study published in the science journal, The Lancet, found that those fully vaccinated with the Pfizer vaccine are likely to produce five times lower levels of neutralising antibodies against the Delta COVID variant.
(The article was first published in FIT and has been republished with permission.)