The surge in COVID-19 cases in South Asia is likely driven by the spread of the JN.1 variant, an Omicron sub-variant. While active, the World Health Organization (WHO) has not yet classified it as a "variant of concern." Fresh cases are rising in India, prompting states to prepare beds, oxygen, medicines, and vaccines. Affected regions include Kerala, Tamil Nadu, Maharashtra, Karnataka, and Delhi. Delhi issued an advisory to hospitals ensuring oxygen bed availability, oximeters, and emergency response teams. Health officials are overseeing preparations, emphasizing hospital readiness.

A new COVID-19 strain, NB.1.8.1, is spreading rapidly in India, believed to be behind the recent surge across 20 states. Health experts warn of its high transmissibility and stealthy spread, even with mild initial symptoms. NB.1.8.1, a subvariant of Omicron lineage JN.1, has been linked to surges in Asia and detected in the United States. This variant was first identified in China and rapidly became the dominant strain, leading to significant case increases. It has also been confirmed in Singapore, Hong Kong, and the United States through airport screenings.

Tamil Nadu reported the first case of NB.1.8.1 in April 2025, and it is closely monitored by Indian health authorities and the WHO. Another subvariant, LF.7, has also been identified in Gujarat. The WHO has designated NB.1.8.1 as a SARS-CoV-2 variant under monitoring (VUM) with increasing proportions globally. Derived from the recombinant variant XDV.1.5.1, NB.1.8.1 was designated a VUM on May 23, 2025, and is one of six VUMs tracked by the WHO.