Covid-19 vaccines work on variant first detected in India but experts fret about the next

Second- or even third-generation versions of the variant known as B1617 could already be circulating in India. PHOTO: AFP

NEW DELHI (BLOOMBERG) - The good news is that the vaccines work against a new coronavirus strain circulating in India that's spread to several other countries. The bad news is it won't be only the new version of the pathogen to emerge from an outbreak of this scale, underscoring the urgency of mapping other possible variants that may be currently racing through India's tightly-packed population of 1.4 billion people.

As infections surge by more than 300,000 cases for 14 straight days, pushing India's tally past 20 million, the country's limited ability to track new mutations emerging from its outbreak is a growing concern for scientists.

Second- or even third-generation versions of the variant known as B1617 could already be circulating in India and some may be more dangerous, said William Haseltine, a former Harvard Medical School professor who now chairs think tank Access Health International.

"India has the necessary genome sequencing capabilities but it needs to have a mass surveillance programme," Haseltine said.

"I'll be on the lookout for more and newer variants, given the opportunity the virus has had with such a massive outbreak."

Variants are already outracing vaccination progress in many parts of the world, fuelling bigger outbreaks that spread faster. While some rich nations that secured effective vaccines early have seen their epidemics wane, the virus is still spreading like wildfire in developing economies, prolonging the pandemic.

Super mutant debunked

Mutations occur when the virus replicates, and India's unprecedented surge is driving new cases to global records, even as richer economies like the US and Israel re-open quickly. Fearing an influx of infections and mindful of B1617, Singapore, the UK and Tanzania are among countries that have curbed travel to and from India.

Australia has banned its citizens from returning from India and imposed penalties of roughly US$50,000 (S$66,786) and five years imprisonment for violators.

The strain first detected in India has been called a double mutant because of the presence of two changes in the virus's genome, called E484Q and L452R. Both affect a portion of the spike protein, called the receptor binding domain, that's key to the virus entering cells.

Some researchers estimate that the B1617 variant is as transmissible as the B117 variant that emerged in the UK, thought to be as much as 70 per cent more transmissible than earlier versions of the virus.

Yet initial analyses indicate that the B1617 version, now classified a variant of interest by the World Health Organisation, poses a limited threat and doesn't appear to be more dangerous.

Covaxin, the inactivated-virus vaccine being made by India's Bharat Biotech International, and AstraZeneca's vaccine, called Covishield in India, are effective against the strain in preventing serious illness, said Rakesh Mishra, director of the Centre for Cellular and Molecular Biology in Hyderabad, one of the labs analysing virus samples.

Data is still being gathered about the response to Russia's Sputnik V vaccine, Mishra said, but it's likely to be effective.

BioNTech chief executive officer Ugur Sahin said he was confident the mRNA shot it's making with partner Pfizer would work against the B1617 variant though testing is still ongoing. The variant "has the same mutation that we've already investigated and against which our vaccine was also effective", he said last week.

Singapore, which tightened social distancing restrictions this week after findings cases linked to the B1617 variant, has also seen vaccines hold up well to prevent serious illness, said Kenneth Mak, director of medical services in city-state's health ministry. But "vaccination does not prevent you from getting infected 100 per cent", he said in a Tuesday briefing.

Ravindra Gupta's team at the University of Cambridge recently studied the two mutations that appear on the receptor binding domain of the B1617 variant's spike protein. The team tested viruses made to simulate the variant against serum from nine people who had already received a single dose of the BioNTech-Pfizer vaccine.

"We wanted to know whether this double mutant really is a double whammy," said Gupta, a professor of clinical microbiology at Cambridge's Institute for Therapeutic Immunology and Infectious Diseases. What they found was that while each of the mutations could partly evade neutralising antibodies, the two mutations didn't combine to create an even greater ability to evade immune protection.

"They don't combine to make a super mutant," Gupta said. "It kind of debunks this view that this double mutant is doubly evading neutralising antibodies."

While the findings ease concerns around B1617, researchers are turning to the next set of variants as India's outbreak continues to rage. Genomic surveillance can provide crucial information on the new forms of this shape-shifting virus - critical in preventing subsequent waves and developing the next generation of vaccines.

In the US, recent studies published by the Centres for Disease Control and Prevention show that a variant that caused concern when it emerged in New York isn't more dangerous than earlier strains, while a pair of mutants that surfaced in southern California "might more frequently cause discernible and severe illness than do nationally circulating lineages overall".

The WHO has been monitoring variants through a global working group of laboratories, said Maria Van Kerkhove, the agency's technical lead officer. Information about new variants is coming in "fast and furious", she said.

But as its health system is stretched to breaking point and Prime Minister Narendra Modi resists calls for a lockdown, the country's labs are ill-equipped to keep up with the necessary monitoring. Genomic sequencing that can identify new strains and track their progress is still relatively sparse in India, where only about 11,000 viruses have been analysed, according to Mishra.

While countries like the UK monitor about 5 per cent to 10 per cent of cases, in India far fewer are sequenced. To do so would require analysing tens of thousands of samples daily, and failing to leaves a huge blind spot, according to Ashish Jha, dean of Brown University's School of Public Health in Rhode Island.

"What genomic surveillance does is it helps you really track where infections are going and how things are spreading in a way India was pretty blind to," he said.

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