Scientists have detected two new virulent sub-variants of Omicron spreading covid-19 infection in India, weeks after sounding the alarm over two others in the run-up to festivities.
A total of 233 cases of sub-variants XBB and seven cases of XBB.1 have been found in various pockets to add to infections caused by the BF.7 and BF.5.1.7 strains detected earlier.
Indian SARS-CoV-2 Genomics Consortium (INSACOG) experts said XBB and XBB.1 are perhaps the most immune-evasive variants to date and evade the immune response of vaccines currently being used to treat covid.
However, none of these four sub-variants are known to have caused hospitalization or death in India.
Concerned over the surge in cases, scientists at INSACOG have kept a close vigil and are monitoring the emergence and evolution of such variants.
Public health experts said people should follow covid-appropriate behaviour to prevent a further spike. XBB was first detected in Singapore and the US and has spread to several countries and Indian states.
Last week, the World Health Organization (WHO) said Omicron remains a variant of concern, with early evidence pointing to XBB and XBB.1 posing a higher reinfection risk than other circulating Omicron sub-lineages.
Rajesh Gokhale, secretary of the department of biotechnology (DBT), said, “In the current phase of the pandemic, the SARS-CoV-2 virus is continuously accumulating mutations, some of which might contribute to increased transmissibility and immune evasion resulting in transmission advantage over other variants. XBB...is presently appearing in multiple countries. A sub-lineage of XBB with an additional mutation is also detected (XBB.1). In India, the Omicron sub-lineages or sub-variants keep diversifying. It has a few new spike mutations.”
“A modest increase in the spread of XBB in Singapore has been observed. However, among Indian patients, the disease is mild, and there has been no report of an increase in severity of disease or increase in hospitalization associated with these variants,” said Gokhale, who heads INSACOG.
“We at INSACOG are closely monitoring the emergence and evolution of XBB and XBB.1 and any new sub-lineages. However, people should not panic and follow strong covid-appropriate behaviour in the light of ongoing festivals,” he said, advising people to mask up in closed environments such as metros and crowded rooms.
INSACOG is a consortium of 54 laboratories to monitor the genomic variations in SARS-CoV-2.
“According to the INSACOG data portal, there are 233 sequences of XBB and seven sequences of XBB.1 in India. XBB and sub-lineages account for over 48% of lineages in the recent weeks of genomic surveillance,” said a scientist aware of the matter who did not want to be named.
Leading public health expert (prof) Dr Srinath Reddy, who is also the president of the Public Health Foundation of India (PHFI), said, “The novel coronavirus is following the path of evolutionary biology, where it can reach a state of co-existence in which it can propagate with ease without decimating its human host population. It seeks the power of greater immune evasion, along with higher transmissibility. Manifest virulence is low due to less capacity to invade the lungs and greater resistance offered against severe disease by acquired immunity among many persons. New forms of the virus should not cause alarm as long as severe disease and death are uncommon.”
India reported 1,604 covid cases in the past 24 hours, and active cases stood at 18,317, health ministry data showed. Since the onset of the pandemic in March 2020, India has reported more than 44.6 million covid cases and 529,016 deaths.
According to INSACOG, Omicron and its sub-lineages continue to be the dominant variant in India.
The country has reported different distributions of “variants of concern’ such as Alpha, Beta, Gamma, Delta, B.1.6 series, AY series, Omicron Series, XE, XM and XJ since the onset of the pandemic.