PUNE: Omicron’s BA.2.75, which for some months has been the most dominant subvariant in parts of India and Maharashtra, is mutating further and likely to become even more transmissible and immune evasive, Insacog scientists have told TOI.
BA.2.75 has spawned what has been designated as BA.2.75.2, which recently drew the attention of experts tracking mutations in SARS-CoV-2. Yunlong Richard Cao, an immunologist at Peking University, tweeted, “BA.2.75.2 is currently the most immune evasive strain we have tested so far.” In India, Maharashtra’s coordinator for genome sequencing, Dr Rajesh Karyakarte, confirmed BA.2.75 is “mutating further”.
“It’s vying for dominance by packing in more immune evasive mutations,” he said.
The BA.2.75.2 subvariant is defined by mutations S:R346T, S:F486S, S:D1199N and was first detected in India as per GitHub. Its earliest sequences were from India, Chile, England, Singapore, Spain and Germany, but is now in over eight countries.
“Maharashtra has found this subvariant in recent samples. It still needs to be seen if this ‘second child lineage’ will dominate the existing BA.2.75. But it is growing,” Dr Karyakarte said. “In 71 recent samples from Pune, 20 had BA.2.75. BA.2.75.1 was in around 11 samples and BA.2.75.2 was found in nearly 17. The rest had other Omicron sublineages. This shows BA.2.75.2 seems to be catching up with BA.2.75,” he said. BA.2.75 and its sub lineages are found in 90% of samples sequenced in Maharashtra.
