The indigenously developed Covaxin is capable of fighting the Brazilian variant too, according to the latest study on Covid-19 vaccine. Earlier, Covaxin was found to fight the UK variant, B.1.1.7, and the so-called double mutant of Maharashtra, B.1.617.
With this the vaccine, developed by the Indian Council of Medical Research in collaboration with Bharat Biotech, is capable of fighting some of the major variants of concern, currently in circulation in the country. Covishield, another Covid-19 vaccine currently available in India, was also found to neutralise the double mutant.
Researchers from the National Institute of Virology, Pune, and the ICMR, New Delhi, studied the neutralisation efficacy of the Brazilian variant, B.18.104.22.168, with the convalescent sera of individuals with natural infection and those, who received two doses of Covaxin. They found that individuals after receiving two doses of Covaxin had their immunity boosted against the Brazilian variant.
The Brazilian variant, which was earlier assigned the technical name, B.1.1.248, is now reclassified as B.1.128.2. Also, the variant was thought to belong to two lineages – P1 and P2. But now, scientists recognise it as one variant with a single lineage. It has been causing trouble in Brazil and some parts of the world. However, in India the Brazilian variant is not as widely present as the double mutant, B.1.617, which is found in about 70 per cent of Covid-19 cases in Maharashtra, or the UK strain, B.1.1.7, which is present largely in Punjab.
Both double mutant and UK variant have been found in several parts of the country, including Andhra Pradesh and Telangana. The double mutant makes up about five to 10 per cent of cases in the two Telugu states. The presence of the UK variant in AP and Telangana is nominal, while that of the Brazilian variant is yet to be established.
“The two-dose vaccine regimen significantly boosted the IgG (immunoglobulin G, a type of antibody) titre and neutralizing efficacy against both B.22.214.171.124 (Brazilian variant) and D614G variants (which replaced the original Wuhan strain last year and became a dominant variant world over) compared to that seen with natural infection. The study demonstrated 1.92 and 1.09 fold reductions in the neutralizing titre against B.126.96.36.199 variant in comparison with prototype D614G variant with sera of vaccine recipients and natural infection respectively,” the research said.
They said the two-dose Covaxin regimen significantly boosted the antibodies and neutralising efficacy against both the variants compared to that seen with natural infection. The result of the study was published in preprint server BioRxiv.
Researchers say although some of the vaccines seem to be effective against the UK variant, the efficacy of them against the South African variant has been demonstrated to be less efficacious. A vaccine that uses an inactivation platform has been reported to be 50.7% efficacious from Brazil, where the B.188.8.131.52 variant is more prevalent.