As various states report a surge in cases of Covid-19, . This was collected and sequenced in April, and has been submitted to India’s Covid-19 genome sequencing consortium INSACOG (Indian Consortium to study and monitor COVID-19 genome) from Tamil Nadu.
Most of the Sar-CoV-2 samples sequenced in India over the last couple of weeks were BA.2 and JN.1 variants. Media reports have highlighted an increase in cases in Singapore and Hong Kong in the last few weeks. As per preliminary information, the cases are mostly mild and not associated with unusual severity or mortality.
As of 18 May, there were 518 NB.1.8.1 sequences submitted to the global Covid-19 genome sequence database from 22 countries, representing 10.7 per cent of the globally available sequences.
Officials sources said that at present there is “no indication that the circulating variants are more transmissible or cause more severe disease compared to the previously circulating variants”.
On Saturday, Covid-19 cases were reviewed by the Union Health Secretary with Secretary, Department of Health Research (DHR) & Director General, Indian Council of Medical Research (ICMR), DGHS, and National Centre for Disease Control (NCDC).
“Some Covid-19 cases have been reported mainly from states like Kerala, , Maharashtra and Karnataka,” official sources said.
“It may be noted that there is a robust pan-India system for surveillance of respiratory illnesses including Covid-19 through the Integrated Disease Surveillance Programme (IDSP) and ICMR’s pan-India respiratory virus sentinel surveillance network. It is observed that most of these cases are under home care,” the sources said.
The World Health Organisation’s Technical Advisory Group on Virus Evolution has designated the Sars-CoV-2 variant NB.1.8.1 as ‘Variant Under Monitoring’ — a variant with significant changes in virus characteristics but whose epidemiological impact remains unclear. The variant comes from a recombinant ancestor XDV.1.5.1, with the earliest samples reported from January 22, 2025. This variant carries six mutations in the spike protein as compared to the currently circulating LP 8.1 and eight mutations as compared to JN.1.
Some of these mutations are known to be linked to increased affinity to the human receptors which could increase its transmission. It could also mean a reduction in neutralisation which could result in the virus evading existing immunity more effectively.
