The recent spike in Covid cases is being attributed to the JN.1 variant, which has become the dominant strain in India, according to data from Indian SARS-CoV-2 Genomics Consortium (Insacog) website.
Barring the eastern region — where Odisha and West Bengal have reported the variant — JN.1 is present in almost all parts of India.
The prevalence is the highest in South, followed by North and West. In the East, only 28.6 per cent of all Covid positive samples tested at Insacog labs in the last week of December are of JN.1. This compares to 100 per cent samples testing positive for JN.1 in the South.
The monthly lineage distribution shows that JN.1 cases have significantly grown in numbers in December last year.
While the genome sequencing is still going on, Insacog data till Sunday, suggests that 503 out of the 536 JN.1 cases have been detected from positive samples in December 2023. The first confirmed case of the JN.1 variant in India was detected by the Insacog in Kerala on December 17.
The sample in question was from a 79-year-old woman from Karakulam in Thiruvananthapuram district. Her RT-PCR positive sample was first collected during routine checking on December 8.
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Since then, Insacog has detected the JN.1 variant in 536 samples across 12 states and union territories, according to figures updated on their website till Sunday morning. Kerala, with 154 cases, has the maximum number of the JN.1 variety. It is followed by 111 cases in Maharashtra, 76 in Gujarat, 51 in Goa, 32 each in Rajasthan and Telangana, 29 in Andhra Pradesh, 22 in Tamil Nadu, 16 in Delhi, eight in Karnataka, three in Odisha and two in West Bengal.
While Insacog claims to provide real-time figures on its website, its data remains limited to JN.1 cases detected till the last week of December 2023.
Zonal distribution of JN.1
Zonal distribution of the JN.1 cases shows that the new variant has affected almost all regions of the country, except for the East, where only Bengal and Odisha have seen cases.
According to Insacog data, XBB.1.16, a combination of two BA.2 strains, was the dominant strain in the eastern region with 57.1 per cent of the cases during the last week of December.
In the last week of December, JN.1 cases accounted for 83.3 per cent of all Covid positive samples at Insacog labs in the northern region. The figure for the western region was 73.1 per cent.
Experts on JN.1
According to experts, the JN.1 variant is a highly infectious descendant of the Omicron subvariant known as BA.2.86 or Pirola.
Speaking on the infectious nature of JN.1, Ambarish Joshi, senior consultant, pulmonary and sleep medicine, Primus Super Speciality Hospital, said it has a single new spike mutation in comparison to Omicron.
This evades immune response easily making it a highly infectious strain that may affect all stages of life.
Speaking on the distinctiveness of the new variant, Joshi said the variant’s uniqueness lies in a fusion of genetic nuances, setting it apart from its counterparts.
“Fever, cough, cold, headache, gastrointestinal disorders and breathing issues are some of the common symptoms of Covid JN.1,” he added.
Tushar Tayal, consultant, department of internal medicine, CK Birla Hospital, said that with the weather conditions favourable for influenza-like illnesses, and higher chances of transmission due to confined spaces, the number of cases is going to increase. The current spike in cases is not the first occurrence of JN.1 in the world.
JN.1 was first found in Luxembourg, and according to the latest numbers, it has been spotted in more than 40 countries. The World Health Organization had declared JN.1 to be a variant of interest in December.