The mind-boggling speed with which the coronavirus overwhelmed Indian health systems has triggered a global alarm over the viral variant that has emerged in the subcontinent.
The B.1.617 variant has been blamed by some for the surge in infections in India, which recorded more than 350,000 confirmed cases as of Monday alone, a world record for a county in a single day. Health experts believed the true figure was likely much higher.
But scientists have urged not to jump to rush conclusions about how much the variant alone is responsible for the skyrocketing increase in cases in recent weeks, which has caused 2,800 confirmed deaths in India as of Monday alone. They said there was little hard evidence for the virulence and transmissibility of the Indian variant and point to other possible factors.
“Despite the alarming spike in new cases with India’s second wave, there is simply not enough evidence to blame the variants,” said Nancy Jaser, infectious disease analyst at GlobalData, a analysis company that follows mutations.
When did the “Indian variant” evolve and to what extent is it widespread?
The Indian variant B.1.617 was first registered in a global viral genome database in early October, just two weeks after the initial detection of the B.1.1.7 variant in the UK. B.1.617 has circulated in India ever since and spread internationally. About 20 countries have reported cases, mostly in travelers from India.
The problem is that, relative to the size of its population, India has done very little full genome sequencing which is the only reliable way to track the evolution of variants. The extent of B.1.617 variant involvement in the outbreak in India is therefore unknown, although it accounts for about two-thirds of the genomes reported by the country to the global GISAID database.
Jeffrey Barrett, director of the Covid-19 Genomics Initiative at the Wellcome Sanger Institute in Cambridge, pointed out that a number of variants were present in India, including one from Britain.
B.1.1.7, which scientists concluded to be more transmissible, was the dominant variant of the Covid-19 wave in the UK at the end of 2020, and then spread to mainland Europe.
“There is evidence of multiple overlapping epidemics in India, rather than a monolithic epidemic,” Barrett said. “Which makes sense because it is a huge and heterogeneous country.”
Is B.1.617 particularly virulent or transmissible?
The original B.1.617 variant has 13 genetic mutations that lead to changes in the virus. These include two in the spike protein which has been linked in other variants (such as those identified in South Africa and Brazil) to increased transmissibility and the ability to evade immunity conferred by the vaccination or previous infection. But there is not yet enough evidence from epidemiological studies or laboratory experiments to confirm that this is also the case for B.1.617.
“You have to watch these things without panicking,” Barrett said. “The fact that [the variant that originated in India] has not spread yet [widely] in the UK, even though it has been off the UK coast since February, suggests that it is unlikely to be as transmissible as B.1.1.7. “
Adding to the uncertainty, B.1.617 itself is “evolving and diverging over time,” according to Sharon Peacock, director of the Covid-19 UK Genomics Consortium. Scientists have already detected three descendants – called B.1.617.1, B.1.617.2 and B.1.617.3 – with slightly different mutations. The practical implications of these strains are unknown.
References in the media and online to “double mutations” in variant B.1.617 were “inaccurate, have no special meaning and should be avoided,” Peacock added.
Will the vaccines be less effective against B.1.617 than against other variants?
Again, it is not clear. Vaccines developed to combat the original coronavirus that emerged in Wuhan in 2019 also appear to work against the B.1.1.7 variant that emerged in the UK, although they appear to be less effective against variants originating in Africa. from the South and Brazil. .
“It is not yet known whether they will maintain their effectiveness against the new variants appearing in India, but they do. . . likely they will at least have some effectiveness, ”said Peter English, a retired UK-based communicable disease consultant.
Since only about 10% of the Indian population has been vaccinated, “variants are not yet under great pressure from vaccine immunity, so there is no great pressure for mutants of. vaccine escapes appear, ”he added.
If the new variant is not the main cause of the Covid-19 crisis in India, what could be responsible?
The evolution of the coronavirus crisis in India was also driven by other factors, including its low vaccination rate and limited hospital capacity, as well as decisions made by leaders such as Prime Minister Narendra Modi and tolerance large political and religious gatherings.
“The focus has been on the B.1.617 variant,” said Michael Head, senior researcher in global health at the University of Southampton in the UK. “But it is the mixing of susceptible populations that ultimately leads to the transmission of infectious respiratory diseases.”
He referred to mass rallies in India in March and April associated with political campaigns, international cricket matches between India and England “with full stadiums and few masks” and several major religious festivals, such as the Kumbh Mela, an event in which millions of people participated.
The Hajj pilgrimage in Saudi Arabia and traditional New Year’s celebrations in China have been much smaller than the Kumbh Mela, Head said.
“India may have reduced its celebrations a bit, but millions of people have gathered for Kumbh Mela at different sites, and thousands of new cases of coronavirus are already confirmed in revelers,” he said. declared.