Covid-19 sub-variant spread: Is JN.1 more infectious?

With WHO classifying it as a ‘variant of interest,’ experts decode what it means and what you need to do.

The uptick in cases globally shows JN.1 — an Omicron sub-lineage — could out-compete other variants due to its high immune escape ability, say experts. That’s why the WHO, given its rapidly increasing spread, has classified JN.1 as a “variant of interest” (VOI), distinct from the parent lineage BA.2.86. The US Centers for Disease Control (CDC) has termed it the fastest growing variant in that country. In India, 21 cases of the Covid-19 sub-variant have already been identified and though there is no need for panic, people are wondering if it is a quick spreader.

‘Increased transmission, immune escape and prolonged infectious period’

Dr Rajesh Karyakarte, genome sequencing coordinator for Maharashtra, says the growth advantage is exponential and cites WHO data that shows how JN.1 rapidly increased from just 3.3 per cent of all coronavirus cases between October 30 and November 5 to 27 per cent a month later. “This is an 86 percent growth advantage,’” says Dr Karyakarte, reasoning that it was due to the increased transmission, immune escape and a prolonged infectious period.

 

This suggests that it is contagious and is getting better at going past the body’s immunity defence than the ancestral strain, according to the CDC. But the spike transmission doesn’t mean that it causes severe disease as hospital admission is low. Experts also say it is a low risk infection and people with prior infection and/or vaccination need not worry.

 

Faster spread due to additional mutation in the spike protein

Genome researchers Vinod Scaria and Bani Jolly have said that the SARS-CoV-2 virus is continuously evolving and forming new lineages. “Every infection provides the virus with the possibility to evolve further and JN.1 is an Omicron sub-lineage that is characterised by an additional spike protein mutation, L455S. The high immune escape property would mean that JN.1 could out-compete other variants,” they say.

A recent  study in Lancet found that the one mutation alone gives JN.1 the ability to evade immune response faster than its parent BA.2.86.

Do we need to worry?

Infectious Disease expert Dr Ameet Dravid says the virus goes through mutations to become stronger and that process will continue. “So far we are treating mild upper respiratory tract infections in a hospital setting. However, there is a possibility of a spike in cases as the variant is more immune evasive. It is important to get vaccinated, especially for those who are partially vaccinated,” Dr Dravid says. There is no stand-out symptom noted yet and manifestations have been similar to earlier variants: a sore or scratchy throat, fatigue, headache, body ache, congestion, coughing and fever.

 

However, as cases show a rising trend, there is a need to make masks mandatory in crowded locations, according to Dr Dravid. It is time to internalise basic respiratory etiquette, like covering your mouth and nose while coughing and sneezing, he adds.

https://indianexpress.com/article/health-wellness/covid-19-cases-sub-variants-jn-1-9076868/