NB.1.8.1 COVID-19 variant cases and symptoms: 7 things to know about this new COVID-19 strain

Kerala remains the most affected, accounting for 335 of the new cases, pushing its active caseload to 430.

The ever-evolving nature of COVID-19 means new variants continue to emerge, keeping the doctors on their toes. One of the latest variants causing concern globally is NB.1.8.1. Here’s what you should know about this new variant:

• NB.1.8.1, new variant:

NB.1.8.1 is a newly identified variant of the COVID-19 virus detected through genomic surveillance in countries including India, Taiwan, Hong Kong, and the United States. Although the World Health Organization (WHO) hasn’t officially labelled it as a Variant of Interest yet, it’s being closely monitored due to its rapid spread.

• NB.1.8.1 cases:

Cases have been reported in several parts of the world, from Tamil Nadu and Gujarat in India to major US airports and even in Taiwan, where it was the predominant strain causing thousands to seek medical care in late April and early May 2025.

• Cause and concerns: 

Scientists have noted key mutations in NB.1.8.1’s spike protein (such as A435S, V445H, and T478I) that could increase how easily the virus spreads and help it evade immune responses. An Australian researcher has observed that NB.1.8.1 may grow faster than other existing variants, suggesting it could quickly become more widespread.

• Symptoms caused by NB.1.8.1: 

Infections have been associated with symptoms like persistent cough, sore throat, fatigue, nausea, and even unusual signs such as blurred vision and low-grade hyperthermia, which is a mild rise in body temperature without a full fever.

• Addressing the variant: 

While WHO is still reviewing this variant, local health organisations like India’s INSACOG and Taiwan’s CDC are already monitoring it. They're reminding everyone to keep wearing masks in crowded places, wash hands often, stay home when sick, and keep up with vaccinations.

• About vaccines: 

Vaccine companies  are working on updates to their COVID-19 shots to make sure they protect against newer variants like NB.1.8.1.

• Stay informed, not scared: This new variant is a reminder that COVID-19 is still with us. The best way to protect yourself and your loved ones is by staying informed, following public health advice, and continuing everyday safety habits. Wash your hands, wear a mask in busy places, stay up to date with your vaccines, and don’t ignore symptoms. Staying cautious is the best way to stay safe.