With cases of Covid-19 on the rise in Kerala, the Union health ministry has written to states and Union Territories, asking them to monitor cases of influenza-like illnesses, conduct adequate testing, and send all positive samples for whole genome sequencing.

These steps come after at least one case of the new variant JN.1 was detected during routine surveillance in Kerala, the health ministry said. This variant was also detected in the sample of a traveller from Singapore to Tamil Nadu's Tiruchirapalli, according to the ministry.

Another 15 cases of the JN.1 variant were detected in samples from Goa, according to officials familiar with the matter, as reported by IndianExpress.

The sub-variant JN.1 is a descendant of the BA.2.86 variant, commonly referred to as Pirola, and is not exactly new. The first cases of this variant were detected in the United States in September and the first case globally was detected as early as January this year.

While JN.1 contains only one additional mutation on the spike protein as compared with Pirola, it has been on the watch-list of researchers because Pirola contains more than 30 mutations on the spike protein. Mutations on the spike protein of Sars-CoV-2 matter because they are the ones that attach to receptors on a human cell and allow the virus to enter it.

There is no evidence to suggest that JN.1 can cause worse symptoms or spread faster than the variants already in circulation. Initially, there were concerns that the high number of mutations could mean that Pirola would evade immune response more easily and spread rapidly. That, however, hasn't happened.

In fact, an assessment by the WHO Technical Advisory Group on COVID-19 Vaccine Composition showed that Pirola and JN.1 were both effectively neutralised by serum from humans who had had the infection and vaccination.

While Pirola and JN.1 are considered to be Variants of Interest (variants that are less effectively neutralised in labs by antibodies from infection or vaccination and have a potential to spread), they have not been designated as Variants of Concern (variants that result in increased transmission, severe disease leading to hospitalisation, and reduce effectiveness of vaccines).