Coronavirus: The Indian variant is on the rise - and public health experts are worried

Dr Sujeet Singh, director of India’s National Centre for Disease Control, told a press conference on Thursday that “the current surge in cases seen over the last one and half months in some states shows a correlation with rise in the B1.617 lineage”.

However, he cautioned that a causal link was “not fully established”.

The variant is the dominant strain in Maharashtra, the epicentre of the current wave, but has also been detected in other states experiencing significant surges such as Gujarat and West Bengal.

In late February India was hailed as reaching the 'endgame' of its pandemic experience, only for a huge second wave to sweep the country

It has also spread to Nepal, which has experienced an explosion in cases over the past month.

To the north of the India, the UK ‘Kent’ strain (B117) - known for it high transmissibility - has been more common, but is now declining as a proportion of total cases.

READ MORE: India's Covid crisis is 'beyond heartbreaking', says WHO 

One theory is that the B1.617 variant - unlike others originating from Brazil and South Africa - is starting to outcompete the Kent variant.

The ‘double mutant’ is only part of the story, of course.

It must be stressed that the surge in Covid in India has occurred within a population with very low vaccination rates (fewer than 10 per cent of its population even now has had a single vaccine dose) coupled with catastrophically lax public health measures.

Prime Minister Narendra Modi

Thousands were allowed to mix freely at political rallies, religious celebrations, and weddings, while India’s Prime Minister Narendra Modi declared at the beginning of March that country was in the “endgame” phase of its battle with Covid.

As recently as February, the virus had seemed to be petering out with daily Covid deaths slipping below an average of 100 per day in a population of almost 1.4 billion.

Antibody data had indicated high levels of virus exposure - as high as 31% in the slums and 50% in Delhi - leading to an assumption that a second wave, if there were one, would be weaker.

Five times as many people in the UK have had a first dose of vaccine compared to India, with most over-70s now having had both doses

In the event, the second wave has swept through India with a ferocity that has astonished scientists, overwhelming hospital beds, wiping out oxygen supplies, and killing 4000 people in the space of a single day this week (and even that is probably an underestimate).

The sub-strain causing the most alarm (in India, and now the UK) is B1.617.2, which was first identified through sequencing in December.

Much like the Kent strain - which emerged in September 2020 but only truly took off in the UK in December - this variant seems to have simmered for months before catching fire.

READ MORE: Why 'eliminating' the virus is better than containment

Clearly, the UK finds itself in a very different position from India.

Already, in Scotland, more than 90% of people over 70 have had both vaccine doses, and 30% of under-50s have had at least a first dose.

That means that while there is still significant scope for spread by the unvaccinated young as the economy continues to open up, the most vulnerable should have high protection.

Yet the Indian strain remains an unknown quantity for now.

It appears to be more infectious - possibly even more so than the Kent variant - but whether it is more virulent or able to escape vaccines remains unanswered.

The number of Indian variant cases being detected each week was "shooting up" while other variants were flatlining and infections caused by the dominant Kent variant were in decline (Source: Prof Christina Pagel @chrischirp)

Nonetheless, public health experts in the UK have now recommended that B1.617.2 should be escalated to a "variant of concern".

A leak on Thursday night revealed that Public Health England considers that it poses a "high" risk to public health amid 48 clusters linked to schools, religious gatherings, and a London care home where 15 residents became infected within a week of their second vaccinations (four were hospitalised with non-severe illness, and none died).

However, the speed of its spread (the Indian variant B1.617.2 may account for up to 50% of non-Kent cases in London now) and evidence of some community transmission led academic and clinical epidemiologist Dr Deepti Gurdasani to warn that “it could easily become dominant in London by the end of May or early June”.

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Healthcare mathematician and Independent Sage member, Professor Christina Pagel compared the data to a ‘canary in the coalmine’ after compiling graphs showing a near vertical surge in Indian variant cases in England, from around 50 cumulatively at March 23 to over 700 by April 20.

It was “growing very fast”, said Prof Pagel, and had notably outpaced any of its rival variants.

While the Kent strain still accounted for more than 90% of Covid cases in England, it was declining in response to lockdown and vaccination; the Indian variant was not.

The spread of the B1617.2 sub-strain of the Indian variant has been unusually fast, and was not linked to travel in many cases (Source: Prof Christina Pagel @chrischirp)

Even excluding travel-related cases or those picked up by targeted surge testing of certain neighbourhoods in England, there was still evidence that the Indian variant was on the rise and - by implication - spreading in the community. Between March 27 and April 24 these cases alone climbed from around five to 120.

In Scotland, 13 cases of the Indian variant were detected in the space of two weeks, up to April 26. In comparison just 10 cases of the Brazilian variant were detected over nine weeks.

The Indian variant, B1.617 is shown in light blue. The South African variant is orange, the Brazilian P1 variant in yellow, and a Nigerian variant in dark blue

While overall infections are falling across the UK, and vaccine progress is heartening, the fact that the Indian variant is spreading comparatively rapidly at a time when all others are falling or stagnant should trigger alarm bells, particularly given that half the population will remain unvaccinated by the time we shift into Level Two on May 17, potentially turbo-charging its transmission.

Finding and quarantining these cases must be a priority.

“Do we have definitive evidence that B1617.2 is more transmissible? No,” tweeted Prof Pagel.

“But honestly I think canaries are chirping - we know it’s in the community and we should act to contain right now while numbers are manageable.”