What Is NB.1.8.1? India’s New COVID Variant - Explained

India has identified a new COVID-19 sub-variant, NB.1.8.1, which the WHO classified as a 'Variant Under Monitoring' (VUM) in May 2025.

First detected globally in January 2025 and linked to the Omicron JN.1 lineage, the Indian case originated from a sample in Tamil Nadu in April. While its spike protein mutations suggest potentially higher transmissibility and immune evasion - featuring eight more mutations than JN.1 - it's not currently deemed a Variant of Interest or Concern.

All You Need To Know About The New COVID Variant

Q: What is the NB.1.8.1 COVID-19 variant, and where was it found in India?

NB.1.8.1 is a newly detected subvariant of the Omicron lineage JN.1. It was identified in a sample from Tamil Nadu and submitted for genome sequencing in April 2025 by India's INSACOG consortium. The World Health Organization (WHO) has classified it as a Variant Under Monitoring (VUM).

Q: Does NB.1.8.1 spread more easily than other variants?

Yes, early data suggests that NB.1.8.1 carries spike protein mutations (A435S, V445H, T478I) that may help it attach more easily to human cells. This potentially increases its transmissibility compared to other variants like LP8.1 and JN.1. However, it is not yet widespread in India.

Q: Is NB.1.8.1 responsible for rising COVID-19 cases in India?

Currently, no. While small case spikes have been reported in Delhi, Andhra Pradesh, Telangana, and Bengaluru, the dominant variant in India remains JN.1, which accounts for 53% of sequenced samples. NB.1.8.1 remains rare.

Q: What are the symptoms of the NB.1.8.1 subvariant?

NB.1.8.1 shares many symptoms with earlier Omicron strains, including:

Mild fever or persistent low-grade temperature

Sore throat, congestion, or mild cough

Headaches and dizziness

Nausea, loss of appetite, stomach discomfort

Fatigue, muscle weakness, and anxiety

Some cases report sleep issues and brain fog

Loss of taste or smell, once common in earlier COVID waves, is now rarely seen.

Q: How dangerous is NB.1.8.1 compared to earlier variants?

Not significantly more dangerous. Both WHO and Indian health authorities report that NB.1.8.1 doesn't lead to more severe illness or increased hospitalization. Most infections reported so far have been mild and manageable at home.

Q: What steps are Indian health authorities taking to track and manage this variant?

Several proactive measures are in place:

Genomic surveillance by INSACOG to track new mutations

State-level advisories to ensure readiness in hospitals

Monitoring and review meetings by national health bodies to assess trends

Public guidance on prevention, testing, and vaccination

States like Delhi and Karnataka have issued advisories, though the situation remains under control.

Q: Are vaccines effective against NB.1.8.1?

Yes. Existing vaccines are believed to offer protection against severe illness and symptoms caused by NB.1.8.1. Previous Omicron exposure may also provide some immunity. Experts suggest considering booster doses, especially for high-risk groups like the elderly and immunocompromised individuals.

Q: What precautions should I take to stay safe?

Health experts recommend continuing these preventive measures:

Stay vaccinated, including booster shots if eligible

Wear N95/KN95 masks in crowded indoor areas

Practice hand hygiene regularly

Get tested if symptoms appear

Self-isolate if unwell to prevent transmission

Follow local health guidelines issued by your state government

Q: Should I be worried about NB.1.8.1 in India?

There is no reason to panic. As of May 19, India has only 257 active COVID-19 cases, with most being mild. NB.1.8.1 is under close watch, and public health systems are responding proactively. Staying informed and following recommended precautions is the best approach.

Q: What should I do if I develop symptoms?

If you experience any of the following:

Persistent low-grade fever

Sore throat, nasal congestion, or cough

Fatigue, gastrointestinal symptoms, or nausea

Headache, dizziness, or difficulty concentrating

You should get tested for COVID-19, stay home, isolate from others, and consult a healthcare provider if symptoms worsen.