Omicron variant BA.2.75's immune-escape ability, wider presence raise concern

The BA.2.75 sub-variant of the novel coronavirus’s Omicron variant has shown wider presence than its other sub-variants, according to infectious diseases expert Dr Ishwar Gilada.

“In the ongoing Covid-19 pandemic, currently, the most prevalent variant globally, the Omicron, has new sub-variants BA.2.74, BA.2.75 and BA.2.76. Of these three, BA.2.75 has shown a wider presence than other two. Currently BA.2.38 is more common and almost 80 per cent of infections are with this sub-variant. Around 10 per cent are BA.2 and the remaining are BA.4, BA.5, BA.2.75,” said Dr Gilada, who is also the Secretary General of Organised Medicine Academic Guild (OMAG).

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According to Dr Gilada, BA.2.75 sub-variant has been seen in 10 Indian states so far—which are wide apart from each other—with Maharashtra dominating with 27 cases, followed by West Bengal at 13, Karnataka with 10 and Madhya Pradesh with seven known cases. Other states, including Delhi, have one or two cases each.

“It has been also seen in seven other countries: Australia, New Zealand, and Japan in Asia and the Pacific region; UK and Germany in Europe; and USA, Canada in North America,” he said.

“With BA.2.75, the most important issue is that it has nine mutations, of which five are in the N terminal domain of the spike protein and that is responsible for the virus attaching to the host cells. These are new mutations and therefore have immune escape both to the immunity acquired through natural infection as well as (through) the vaccination,” the OMAG said in a statement.

The sub-variant’s immune escape, hence, becomes a point of concern.

“However, so long as it doesn't end up creating oxygen demand, bed demand and more deaths, nothing much to worry about. We need to continue vigilance with continued genome sequencing and producing new generations of vaccines that can provide protection against all the strains prevalent now and possible variants in near future,” said Dr Gilada.