'Omicron likely to be last Covid variant'

Given that Omicron’s infection mechanism, etc, are so different from other Covid variants, it can be called a Covid ‘deviant’ rather than variant, the paper says

Omicron is likely to be the last Covid variant, and another Covid wave is unlikely, according to a recent article co-authored by prominent virologist Dr Jacob John. The article appeared on April 25 in the journal Current Science, published by the Indian Academy of Sciences, Bengaluru.

It looks at evidence from various studies to understand why Omicron had more mutations than other Covid variants, and why it is more transmissive and immune-evasive.

SARS-CoV-2 virus, which is similar to polioviruses, is expected to mutate slowly and predictably. But Omicron had a very high number of mutations and several sub-variants like BA.2 in a short time span, unlike previous variants like Delta.

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This is because Omicron was transmitted from humans to animals, which then circulated and mutated within the animal species, and was eventually transmitted back to humans, the study hypothesises. “This is a very rare event, it has no precedent. The likelihood of this happening again is low, so another Covid variant is unlikely,” Dr John told DH.

Given that Omicron’s infection mechanism, transmission rates, etc, are so different from other Covid variants, it can be called a Covid ‘deviant’ rather than variant, the paper says. “It immunised unvaccinated populations while causing only mild symptoms. Though different, it’s still coronavirus, and its infection protects against any future variant,” said Dr John. This herd immunity should be kept up through vaccinations, the paper adds.

It also says that Covid is unlikely to be eradicated as it exists among animals now. Also since some Omicron sub-variants have high transmission efficiency they should be closely watched.

Virologist and Technical Advisory Committee (TAC) member Dr V Ravi agrees that future variants are unlikely. “Since the population already has core immunity against Covid, the virus has no pressure to mutate drastically. But the disease will remain, and will spurt whenever there are mutations.”

He, along with TAC member and virologist Dr Giridhar Babu, says that surveillance measures have to continue. Dr Babu says, “We have to continue a vigilant and proactive approach. Even if the disease is endemic now, without monitoring we wouldn’t know if it crosses the threshold of endemicity in future.”