Covid-19 Delta subvariant: amid rising concerns in Britain, what was India’s experience like?
- Mutations of the Delta variant have not been more malevolent than the parent
- But the subtype causing concern in Britain is AY.4.2, which has ‘nothing to do’ with India’s experience of Delta Plus variants, says an expert
The country of 1.3 billion people has also grappled with mutations of the Delta variant – broadly referred to as Delta Plus – yet they have proven to be no more unruly or malevolent than its parent that brought the country’s medical system to its knees earlier this year.
Still, experts say India’s experience with mutations of the Delta variant may not necessarily be instructive for Britain. For one, the mutations in India are largely the AY.1 and AY.2 variants. India has had some cases of the AY.4 variant, but the one now causing concern in Britain is the AY.4.2 subtype, which is a combination of AY.4 and the S:Y145H spike mutation.
“In India, the dominant Delta sub-variant is AY.1 and AY.2,” said Dr Anurag Agrawal, director at the CSIR Institute of Genomics and Integrative Biology in New Delhi.
“All of them are Delta, but the Indian experience with AY.1 and AY.2 has nothing to do with the AY.4.2 lineage which is causing concern in the UK right now.”
Dr Agrawal said genome sequencing had shown that India’s Delta Plus variants had no special characteristics; they were pretty much as infectious and as serious as the Delta variant but no more.
But nothing of the kind happened. The handful of first cases found in a couple of states made the news. It was initially classified as a “variant of concern” by public health officials, who said some studies showed it could spread more easily, bind more easily to lung cells and could potentially resist monoclonal antibody therapy.
But nothing much was heard of it again. Probably the last official comment on it came on September 2, when Balram Bhargava, Director General of the Indian Council for Medical Research, was asked what happened to it during a Covid-19 press briefing.
Bhargava said 300 cases of the Delta Plus variant had been found since June 11 and the efficiency of the vaccine had been tested against this strain.
“It has been some months since the isolation of the Delta Plus variant … it has been isolated and vaccine efficacy has been tested against it. The vaccine is found to be effective against Delta Plus,” he said.
Since India is poised to administer its 1 billionth vaccine to great fanfare some time this week, it may explain why the pandemic is under control and why the virus seems to be in total retreat across the country.
Even Kerala and Maharashtra, the two worst affected states, have not seen any high incidence of difficulties caused by the Delta Plus variant.
While vaccinations continue, new infections – around 14,000 – are at their lowest rate for seven months. The figure is significantly lower than the one in the UK, which has a much smaller population but recorded 50,000 new virus cases on Wednesday, one of the worst daily infection rates in the world.
About 75 per cent of Indians have received one vaccine jab and about 30 per cent have received two doses.
Experts had feared that a third wave might hit the country in October or November, but despite opening up and people moving around much more freely, there is so far no sign of a new outbreak.
“What is heartening to know from our genome sequencing is that there is no evidence to prove the emergence of a new variant. Many of us now feel that a new wave can be avoided,” said Dr Suneela Garg, who heads the coronavirus task force in the Indian capital.
Top virologist Dr T Jacob on Tuesday said the chances of a third wave were remote. “The coronavirus pandemic in India has transitioned into an epidemic stage. We need to forget about the third wave for the moment. If it does come up, it will be mid or the last quarter of next year,” he said.
The contrast with Britain’s current surge is striking. Infection rates have soared in spite of a high vaccination rate, prompting former US Food and Drug Administration commissioner Scott Gottlieb to express concern and ask for urgent research to figure out if “this Delta Plus is more transmissible, has partial immune evasion”, he said on Twitter.
British Prime Minister Boris Johnson’s government says it is early to say for certain if the AY.4.2 subtype is responsible for the spike in infections. Experts who spoke to US health website Health.com for an October 18 article on the subtype agreed.
Infectious disease expert Dr Amesh A. Adalja, a senior scholar at the Johns Hopkins Center for Health Security, said: “There’s no significance in whether they change the behaviour of the virus or not, and there has not been any conclusive evidence that they’re anything above and beyond the Delta parent strain.”