๐ Public Health Alert: NB.1.8.1 Variant Spreading Across Asia and Beyond
ONGOING ALERT – TO BE UPDATED AS MORE INFORMATION BECOMES AVAILABLE
A new COVID-19 variant, NB.1.8.1, also called Nimbus, has been identified as responsible for a resurgence of cases in several Asian countries, including India, Hong Kong, Singapore, and Thailand. This variant, a descendant of the Omicron subvariant JN.1, has been designated a Variant Under Monitoring (VUM) by the World Health Organization due to its increasing global presence and potential implications for public health.
๐ Global Impact
- India: As of May 27, 2025, India has reported over 1,000 active COVID-19 cases, with 104 cases in Delhi alone. The NB.1.8.1 variant has been detected in Tamil Nadu, while another subvariant, LF.7, has been identified in Gujarat.
- Hong Kong and Singapore: Both cities are experiencing significant spikes in COVID-19 cases. In Singapore, weekly cases increased from 11,100 to 14,200 in early May.
- Thailand: A notable surge has been observed, with cases rising from 6,000 to over 33,000 within a few days.
- It has spread throughout 22 countries so far. In the U.S., it has been traced to New York, California, Arizona, Ohio, and Rhode Island, according to Gingko Bioworks, the CDCโs airport testing partner.
๐งฌ Variant Characteristics
- Transmissibility: NB.1.8.1 appears to be more transmissible than previous variants contributing to rapid increases in case numbers in affected regions.
- Symptoms: Commonly reported symptoms include a severe sore throat described as โrazor-blade throat fatigue, mild cough, fever, muscle aches, and congestion.
- Severity: Limited data is available on severity as weeks are required for infections to develop.
- Seasonality. The emergence of this new variant in the summer belies the notion that Covid-19 is a cold-weather seasonal illness.
๐ก๏ธ Recommended Precautions
To mitigate the spread of NB.1.8.1 and protect public health, WHN recommends:
- Monitoring: if available, consult your local wastewater readings to assess increasing levels of COVID-19 in your area.
- Masking: wear high-quality masks (e.g., N95 respirator-grade masks) when you are with people outside of your household, and particularly in crowded or indoor settings.
- Clean Air: improve indoor air quality by opening windows, improving ventilation and using HEPA air purifiers.
- Testing: get tested if symptomatic or after known exposure to COVID-19.
- Isolation: avoid in-person meetings and other exposure risks, and stay home if feeling unwell to prevent potential transmission.
- Vaccination: stay up to date with COVID-19 vaccinations and boosters, especially if in a high-risk group.
Public health authorities continue to monitor the situation closely. While the current risk assessment does not indicate a cause for alarm, continued vigilance and adherence to preventive measures are essential.
For more information and updates, visit WHN.global.
First draft generated by GPT. Edited by members of the Covid Action Group
[6] https://www.cbsnews.com/news/us-reports-cases-new-covid-variant-nb-1-8-1-behind-surge-china/
[7] https://whn.global/stop-transmission-with-the-five-pillars-of-protection/
