‘Double mutant’ variant now also spreading in UK
UK health authorities announced that they have detected at least 77 infections with B.1.617 variant first found in India and have designated it as a VUI, or variant under investigation, with experts expressing concern at the sudden spurt in its prevalence.
B.1.617 has also been called the ‘double mutation’ variant in India, where authorities found it in high numbers among people in Maharashtra at the start of the wave in March that has now driven an unprecedented surge in infections.
“PHE has identified 77 cases of this variant in the UK and all appropriate public health interventions will be undertaken, including enhanced contact tracing. This variant has been designated VUI-21APR-01. PHE and international partners continue to monitor the situation closely,” said the April 15 update by Public Health England (PHE).
World Health Organization (WHO) officials too said they were treating it as a variant of interest. “This is a variant of interest we are following,” Maria Van Kerkhove, the WHO’s technical lead officer on Covid, told reporters on Friday, Bloomberg reported.
“Having two of these mutations, which have been seen in other variants around the world, are concerning,” she said, adding that there was a similarity with mutations that increase transmission as well as reduce neutralisation, possibly stunting the ability of vaccines to curb them.
The variant is now among seven that is under investigation by the UK health agency. It was found in 73 infections in England and four in Scotland, the latest of PHE’s weekly briefing said.
“77 appears to be a relatively high number of first detected cases for the B.1.617 variant under investigation first detected in India... I await PHE’s expert analysis of the particular risks of B.1.617,” said Dr Duncan Robertson, a policy expert at Loughborough University, in a tweet.
Typically, new variants begin appearing gradually in samples if surveillance is adequate. The Covid-19 genomics UK consortium (COG-UK) sequences roughly 10% of all cases, a rate that experts say India must attempt to match.
The Indian Sars-CoV-2 Consortium on Genomics (Insacog), by comparison, has 13,614 sequences since it began functioning in December, the Union health ministry said on Friday. This comes to about 0.34% of the 3.9 million positive cases recorded in India since January 1, 2021.
An analysis of genome sequences uploaded by Indian scientists to the global repository of viral pathogen GISAID Initiative has shown that the B.1.617 has been found in increasing number of samples of late, becoming the most common of variants to be detected in the 60 days up till April 2.
While Indian authorities are yet to disclose this data, top officials have said that it is increasing in prevalence. “From barely existing in December, it is now found pretty much everywhere we look. We have a separate column for the variant for every state now,” said Anurag Agarwal, director, Institute of Genomics and Integrative Biology, one of the 10 labs under Insacog, on Thursday.
Once studies determine that a VUI can cause a more severe outbreak or evade immunity conferred by a vaccine or a previous infection, it is classified as a VOC, or a variant of concern.
B.1.617 has two mutations -- E484Q (glutamate is replaced by glutamine at the 484th spot of the spike protein) and L452R (substitution of leucine with arginine at the 452nd position) – among others that are being investigated for giving the virus an ability to evade immunity.
L452R has also been found in a variant spreading in California, US, where it was implicated in a large outbreak earlier this year.
At present, there are five VOC’s. The first, B.1.1.7 was found in the UK and has been confirmed to be more transmissible and was also implicated in a large resurgence of cases across the UK.
US considers the California variant as VOC as well, while globally, the other VOCs are the South African variant (B.1.351) and the Brazilian variant (P.1).
“As on 15/04/2021, 13,614 WGS (whole genome samples) samples have been processed at the 10 designated INSACOG labs. Of these, 1,189 samples have tested positive for variants of concern for Sars-Cov-2 in India. This includes 1,109 samples with UK variants; 79 samples with South African variant and 1 sample with the Brazil variant,” the Union health ministry said on Friday. It did not give a breakdown of how many were found in samples from travellers or those taken from community sampling.
The government added that the test kits being used in India “do not miss these mutations as the RT-PCR tests being used in India target more than two genes”. The clarification was amid increasing anecdotes from several parts of the country that there has been a rise in false negatives.
“The detection of these mutations does not change the strategy of management which remains to test, track, trace and treat. The use of masks remains as the most important shield to prevent the spread of Covid 19,” the health ministry statement added.