India variant as global concern
India has recorded the world's sharpest spike in coronavirus infections, with major cities running out of hospital beds, oxygen and medicines.
Scientists are studying what led to the unexpected surge, and particularly whether a variant of the novel coronavirus first detected in India is to blame. The variant, named B.1.617, has been reported in 17 countries, raising global concern.
The B.1.617 variant contains two key mutations to the outer "spike" portion of the virus that attaches to human cells, said senior Indian virologist Shahid Jameel.
The World Health Organization (WHO) said the predominant lineage of B.1.617 was first identified in India last December, although an earlier version was spotted in October 2020.
On 10 May 2021, the WHO classified it as a "variant of concern," which also includes variants first detected in Britain, Brazil and South Africa. Some initial studies showed the Indian variant spreads more easily.
There is increased transmissibility demonstrated by some preliminary studies," Maria Van Kerkhove, WHO's technical lead on Covid-19, said, adding it needs more information about the Indian variant to understand how much of it is circulating.
VUI, VOU & VOC
The World Health Organisation on 10 May 2021 classified a coronavirus variant first identified in India as a “global variant of concern”. This variant called B.1.617 was classified as a variant under investigation (VUI) by authorities in the UK earlier in May. It has already spread to more than 17 countries and several countries have put travel restrictions for passengers coming from India as a result of the surge in cases here.
The WHO says that a variant of interest (VOI) becomes a variant of concern (VOC) if, through a comparative assessment, it has been demonstrated to be associated with increase in transmissibility or detrimental change in COVID-19 epidemiology, increase in virulence or change in clinical disease presentation or a decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics. Alternatively, a variant may be classified as a VOC by the WHO in consultation with the WHO SARS-CoV-2 Virus Evolution Working Group.
Recently, the Indian government said that this variant also called the “double mutant variant” could be linked to a surge in the cases of coronavirus seen in some states. This admission was a change in the Centre’s previous stance when it said that the strain was not identified in enough samples to establish a sufficient link to the current surge. Even so, the government said that the link was not “fully established”.
Earlier in March, India’s Health Ministry said that a new “double mutant variant” of the coronavirus had been detected in addition to many other strains or variants of concern (VOCs) found in 18 states in the country.
B.1.617 was first designated as a VUI on 1 April 2021 by the UK health authorities who requested India to send samples of the B.1.617 strain to carry out wider studies on it and determine how effective existing vaccines are against it.
Variants of a virus have one or more mutations that differentiate it from the other variants that are in circulation. While most mutations are deleterious for the virus, some make it easier for the virus to survive.
Essentially, the goal of the virus is to reach a stage where it can cohabitate with humans because it needs a host to survive. This means, any virus is likely to become less severe as it keeps evolving, but in this process it can attain some mutations that may be able to escape the body’s immune response or become more transmissible.
The SARS-CoV-2 virus is evolving fast because of the scale at which it has infected people around the world. High levels of circulation mean it is easier for the virus to change as it is able to replicate faster.
The B.1.617 variant of the virus has two mutations referred to as E484Q and L452R. Both are separately found in many other coronavirus variants, but they have been reported together for the first time in India.
The L452R mutation has been found in some other VOIs such as B.1.427/ B.1.429, which are believed to be more transmissible and may be able to override neutralising antibodies. The WHO has said that laboratory studies suggest that samples from individuals who had natural infection may have reduced neutralisation against variants which have the E484Q mutation. Public Health England (PHE) says that if the variants of SARS-CoV-2 are considered to have concerning epidemiological, immunological or pathogenic properties, they are raised for formal investigation.
At this point, the variants emerging from the B.1.617 lineage are designated as Variants Under Investigation (VUI) with a year, month, and number (For instance, the three variants first identified in India are called VUI-21APR-01, VUI-21APR-02 and VUI-21APR-03) by PHE. Following a risk assessment with the relevant expert committee, the variants identified in India may be designated Variant of Concern (VOC) by the UK health authority.
The US Centers for Disease Control and Prevention (CDC), on the other hand classifies variants into three categories– variant of interest (VOI), variant of concern (VOC) and variant of high consequence. In the US, the B.1.526, B.1.526.1, B.1.525 (previously designated UK1188 and first identified in the UK), and P.2 (identified first in Brazil) variants. On the other hand, the B.1.1.7, B.1.351, P.1, B.1.427, and B.1.429 variants circulating in the US are classified as variants of concern.
The CDC defines a VOI as, “A variant with specific genetic markers that have been associated with changes to receptor binding, reduced neutralization by antibodies generated against previous infection or vaccination, reduced efficacy of treatments, potential diagnostic impact, or predicted increase in transmissibility or disease severity.” While a VOC is defined as “A variant for which there is evidence of an increase in transmissibility, more severe disease (e.g., increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures.” So far, the CDC has not found variants of high consequence in circulation in the US.
ARE VARIANTS DRIVING THE SURGE IN CASES?
It's hard to say. Laboratory-based studies of limited sample size suggest potential increased transmissibility, according to the WHO.
The picture is complicated because the highly transmissible B.117 variant first detected in the UK is behind spikes in some parts of India. In New Delhi, UK variant cases almost doubled during the second half of March, according to Sujeet Kumar Singh, director of the National Centre for Disease Control. The Indian variant, though, is widely present in Maharashtra, the country's hardest-hit state, Singh said.
Prominent US disease modeller Chris Murray, from the University of Washington, said the sheer magnitude of infections in India in a short period of time suggests an "escape variant" may be overpowering any prior immunity from natural infections in those populations.
"That makes it most likely that it’s B.1.617," he said. But Murray cautioned that gene sequencing data on the coronavirus in India is sparse and that many cases are also being driven by the UK and South African variants.
Carlo Federico Perno, Head of Microbiology and Immunology Diagnostics at Rome's Bambino Gesù Hospital, said the Indian variant couldn't alone be the reason for India's huge surge, pointing instead to large social gatherings.
DO VACCINES STOP IT?
One bright spot is that vaccines may be protective. White House chief medical adviser Anthony Fauci said that preliminary evidence from lab studies suggest that Covaxin appears capable of neutralizing the variant.
Public Health England said it was working with international partners but that there is currently no evidence that the Indian variant and two related variants cause more severe disease or render the vaccines currently deployed less effective.
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