Covid cases rising in Singapore, India: What's JN.1 variant driving the surge, its symptoms, severity, precautions and vaccine response

Covid 19 is back! Yes, after creating mayhem in the world from 2019-2022, the virus is seeing a gradual return to Asia with Singapore and Hong Kong recording the maximum number of cases in the last few weeks. Closer home, the country saw two Covid related deaths in Mumbai last week, both of whom also had comorbidities along with Covid 19. While the disease is still endemic, and (for now) poses no immediate threat according to the government, what is this new variant, and what makes it different from the rest? Let's dig deeper...

Two fast spreading variants

The sudden surge is being driven by two fast-spreading sub variants—OF.7 and NB.1.8—both of which are descendants of the JN.1 lineage, itself a subvariant of the Omicron strain.

Variant of "interest"

The World Health Organization (WHO) has classified JN.1 as a “variant of interest” due to its rapid transmission, though it has not been labeled a “variant of concern," at least for now. Its descendants, LF.7 and NB.1.8, are now under global observation.

What’s driving the sharp spike

The sharp increase in cases is primarily linked to increased transmissibility of these sub variants and a gradual waning immunity in the population. This means that while everyone has had got covid at some point in their life, that immunity is now decreasing naturally.

This shift in variant dominance has led to a 28% rise in infections in Singapore during the week ending May 3, 2025. Similarly, Hong Kong has observed a significant increase in cases, with COVID-19 test positivity jumping from 6.21% to 13.66% over a four-week period, indicating rapid spread of these variants.

Experts say the rise is also influenced by reduced protection from prior infections or vaccinations, increased social mixing, and relaxed preventive behavior. Seasonal effects may also play a role in amplifying transmission during certain periods.

How is this variant different, what are the symptoms

So far, the symptoms linked to LF.7 and NB.1.8 remain consistent with other Omicron sub variants. These include:

Sore throat
Mild cough
Fatigue
Fever

Is the variant severe

As of now, there is no data that proves that this variant is any more severe than the earlier ones. Interestingly, the loss of taste and smell, reported in other variants of Covid (especially the Delta one, which caused the devastating 2nd wave of Covid in India in early 2021), is not being seen in this variant, till now.

Health authorities across the region report that most cases remain mild, especially among vaccinated individuals. However, older adults and those with underlying health conditions remain more vulnerable to complications.

Vaccine is still the best protection, say doctors

To mitigate the spread, the Ministry of Health recommends that high-risk groups, such as the elderly and immunocompromised, receive booster vaccinations. Additionally, the public is advised to practice standard precautions, including mask-wearing in crowded places, regular handwashing, and staying home when unwell.

How can you protect yourself

Protecting yourself against Covid means going back to the basics. This includes:

Get vaccinated: Vaccines continue to protect against severe illness.

Wear masks in crowded or indoor places: Using masks in high-risk settings are important. This reduces the chance of catching or spreading the virus.

Practice good hand hygiene: Wash hands regularly with soap or use sanitizer.
Avoid close contact with sick people: If you feel unwell, stay home and seek medical advice.

Stay informed: Follow updates from reliable health authorities about local COVID-19 trends and guidelines. Do not fall prey to fake news.