Covid 19 is unfortunately back. Yes, after wreaking havoc 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 has been seeing a rise in variant NB.1.8.1 and LF.7 variants, detected recently in different parts of the country. 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? While it shares many features with previous Omicron sub variants, there are two notable symptoms that stand out as different in JN.1 infections. Let's dig deeper...
What is the JN.1 COVID-19 Variant?
JN.1 is actually a subvariant of the Omicron, evolving from the BA.2.86 variant, also known as Pirola. It was first identified in Luxembourg in 2023 and since has gradually spread to other parts of the world, and now India. JN.1 is said to be more transmissible than previous variants due to specific mutations in its spike protein, which helps it binds to humans easily. However, as of now, there is no data to prove that it causes any serious illness.
See More: COVID-19 resurges: Are the XFG, NB.1.8.1, and LF.7 variants more transmissible - early symptoms and severityCommon Symptoms of JN.1
Most symptoms of JN.1 are similar to other Omicron variants and include the usual:
Fever or chills
Dry cough
Sore throat
Fatigue
Headache
Runny or blocked nose
Muscle aches
Shortness of breath (in severe cases)
These symptoms usually appear 2 to 14 days after exposure and are often mild, with patients recovering quickly at home only.
The two different symptoms
While many symptoms overlap with previous COVID-19 strains, two symptoms have been reported more frequently or distinctly in JN.1 infections:
Persistent Low-Grade fever
Unlike earlier variants where high fever with sweating and chills was common, JN.1 infections often cause a persistent low-grade fever, typically between 37.6°C and 38.1°C.(99.6-100.5°F) This fever does not show regular symptoms like rapid breathing, or warm to the touch. Instead, it alters the body's temperature regulation, known as hyperthermia. People may feel slightly warm for several days without the intense fever spikes seen in previous COVID waves.
This symptom can be easily overlooked or mistaken for mild tiredness or other minor illnesses. The continuous mild fever signals the body is fighting the virus but in a less aggressive way than before. Recognizing this can prompt early testing and isolation to prevent spread to others.
Gastrointestinal issues
Another symptom that sets JN.1 apart is the increased frequency of digestive issues such as nausea, loss of appetite, stomach discomfort, and diarrhea. While gastrointestinal symptoms were present in earlier COVID-19 variants as well, they were less common and often mild. With JN.1, these symptoms seem to be more prominent and affect a larger number of patients.
According to doctors, this change may be due to the virus’s altered behavior in the body or its interaction with the gut’s immune system. Digestive symptoms can sometimes appear alongside or even before respiratory symptoms like cough and sore throat, which is different from earlier strains. On the other hand major respiratory issues have not been reported in this strain.
Why the difference
The unique symptoms of JN.1 arise from its genetic mutations, especially in the spike protein. These mutations make the virus more contagious by its quick ability to bind to human cells. However, they do not seem to increase the severity of illness. Instead, the virus causes a different pattern of symptoms, reflecting subtle changes in how it affects the body.
What Should You Do If You Experience These Symptoms?
If you notice a mild, continuous fever without sweating or chills, or if you develop nausea, loss of appetite, or stomach discomfort along with respiratory symptoms, it is wise to:
Get tested for COVID-19 to confirm infection, especially if you have been exposed to someone with the virus or have recently traveled.
Self-isolate to avoid spreading the virus to others.
Stay hydrated and rest well.
Monitor symptoms carefully, and seek medical help if you experience breathing difficulties.
Keep your vaccinations up to date, including boosters, as they still remain your best bet against severe illness.
Where Are These Variants Found in India?
NB.1.8.1: First detected in Tamil Nadu in April 2025.
LF.7: Four cases confirmed in Gujarat in May 2025.
Other states reporting active COVID-19 cases linked to these or other variants include Kerala, Maharashtra, Karnataka, Delhi, and several northeastern states. Kerala currently has the highest number of cases, followed by Tamil Nadu and Maharashtra. The rise, while noticeable, is not yet worrisome.
Impact on Vaccines and Treatments
Current vaccines and treatments remain effective against these new variants. Health authorities emphasize the importance of vaccination and boosters to maintain protection. There is no indication that NB.1.8.1 or LF.7 significantly evade immunity from vaccines or past infections, unlike some earlier variants that partially escaped immune responses.
Stay safe, but don't panic
Despite its unique symptoms, JN.1 is not more dangerous in terms of severity but spreads more easily. Therefore, preventive steps remain key to controlling its impact:
Wearing masks in crowded or enclosed spaces.
Practicing good hand hygiene.
Avoiding close contact with sick individuals.
Following public health advice on vaccination and boosters.
If you experience any of these symptoms it is important to talk to your healthcare provider.
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