Bharat Biotech’s coronavirus vaccine, Covaxin, is effective against Delta plus and other emerging variants of the infection, according to a new study by the Indian Council of Medical Research released on Sunday. However, the percentage of efficacy of the vaccine against these strains is not known.

The Delta plus variant, or AY.1, is a sub-lineage of the Delta strain, which was first detected in India in October. The Delta variant was responsible for the devastating second wave of the pandemic in India, a central government study showed in June.

In the study, researchers measured the antibody activity in emerging variants such as Delta, Delta plus and the B.1.617.3 strains, according to The Print. This was then compared with the reaction of antibodies to the B.1 variant, which is one of the first identified strains of Covid-19.

The B.1 variant mutated into the alpha, beta, gamma and delta variants.

Researchers noted that there was a minor reduction in the antibodies’ ability to neutralise these variants compared to the B.1 strain. However, despite this reduction, the vaccine was still effective against all these variants, the study concluded.

Samples were collected from individuals who had recovered from Covid-19, those who have received both doses of Covaxin, those who had contracted and recovered from the infection after getting inoculated and those who were vaccinated but had never had the infection.

Dr Samiran Panda, the head of epidemiology and communicable diseases at the ICMR, told The Indian Express that the conclusion of the study was that Covaxin was effective and the slight reduction in the level of antibodies would not be “detrimental for the vaccination programme”.

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The Delta strain has so far reached 132 countries and territories, with some even reporting new waves of infections caused by the variant. The mutation shows increased transmissibility and has the potential to escape antibodies.

Covaxin, an indigenous vaccine, has been developed by Bharat Biotech in collaboration with the Indian Council of Medical Research. The study on the vaccine’s effectiveness against the Delta plus variant was published on pre-print server bioRXiv. It has not been peer reviewed yet.

Data released in July said that Covaxin is 65.2% effective against the Delta variant of the coronavirus.

Only 70 cases of the Delta plus variant of Covid-19 have been registered in India so far, PTI reported last week.

India on Monday recorded 40,134 new coronavirus cases, taking the tally of infections to 3,16,95,958 since the pandemic broke out in January last year. With 422 deaths, the country’s toll rose to 4,24,773.