As we move through 2025, a new COVID-19 variant has emerged, drawing the attention of health experts and the public worldwide. Known as NB.1.8.1, this variant is part of the Omicron family and has rapidly spread across Asia, Europe, and North America. Here’s what you need to know about this latest development in the ongoing COVID-19 story.
What Is the NB.1.8.1 Variant?
NB.1.8.1 is a sublineage of the Omicron variant, first identified in China in January 2025. It quickly became the dominant strain in several Asian countries, leading to increased cases and hospitalizations. The World Health Organization (WHO) has classified NB.1.8.1 as a Variant Under Monitoring, meaning it’s being closely watched but is not currently considered a major global threat.
Key Features of NB.1.8.1
- Belongs to the Omicron JN.1 sublineage
- Contains new spike protein mutations (such as T22N, F59S, G184S, A435S, V445H, T478I)
- Shows increased ability to bind to human cells
- Spreads faster than previous variants, but does not appear to cause more severe illness
Where Has NB.1.8.1 Spread?
NB.1.8.1 was first detected in China, where it quickly led to a surge in COVID-19 cases and hospitalizations. The variant has since been found in:
- Hong Kong
- Singapore
- Taiwan
- United States (California, Washington, Ohio, Rhode Island, Hawaii, and others)
- Several European countries (France, Germany, Ireland, Sweden, Netherlands, Spain)
- Australia
- India (isolated cases in Tamil Nadu and Gujarat)
Table: Global Spread of NB.1.8.1 (as of May 2025)
| Region | Status | Notable Impact |
|---|---|---|
| China | Dominant variant | Surge in ER visits, hospitalizations |
| Hong Kong | High prevalence | Highest cases in a year |
| United States | Detected, not dominant | Limited community spread |
| Europe | Detected | Monitoring ongoing |
| India | Isolated cases | No major surge |
Symptoms and Severity
The symptoms of NB.1.8.1 are similar to those of other Omicron variants. Most people experience mild to moderate illness.
Common Symptoms
- Sore throat
- Fatigue
- Mild cough
- Fever
- Muscle aches
- Nasal congestion
Some patients have reported persistent low-grade fever, headaches, nausea, loss of appetite, and mild digestive issues.
Severity
- No evidence suggests NB.1.8.1 causes more severe illness than previous variants
- Hospitalizations have increased in some countries due to higher case numbers, not because the variant is more dangerous
- Most severe cases and deaths are among older adults and those with underlying health conditions
How Transmissible Is NB.1.8.1?
This variant spreads more easily than many earlier strains. Its spike protein mutations help it bind more effectively to human cells, making person-to-person transmission more efficient. However, it does not appear to evade immunity from vaccines or past infections any more than other recent variants.
Are Current Vaccines Effective?
Early studies show that existing vaccines, especially those updated for Omicron subvariants, still offer protection against NB.1.8.1. Vaccine makers like Moderna and Pfizer have reported that their latest shots, based on the LP.8.1 strain, provide good cross-protection.
Key Points on Vaccines
- Updated vaccines targeting Omicron JN.1 sublineages are recommended
- The FDA advises using LP.8.1-based vaccines for the 2025-2026 season
- Vaccines reduce the risk of severe illness, hospitalization, and death
Public Health Response
Countries are responding based on their local situations:
- China, Hong Kong, Singapore, Taiwan: Increased hospital preparedness, public health messaging, and stockpiling of vaccines and treatments
- United States: Enhanced airport screening, genomic surveillance, and ongoing vaccine updates
- India: Monitoring with no major policy changes, as cases remain low
Mask-wearing, especially in crowded or enclosed spaces, is being encouraged in some regions experiencing surges.
What Should You Do?
To protect yourself and others:
- Stay up to date with COVID-19 vaccinations, especially if you are in a high-risk group
- Practice good hand hygiene
- Wear masks in crowded or poorly ventilated spaces if local health authorities recommend it
- Monitor for symptoms and get tested if you feel unwell
- Follow local health guidelines and updates
The Bottom Line
The NB.1.8.1 variant is spreading quickly in some parts of the world, but it does not appear to be more dangerous than previous strains. Vaccines remain effective, and most people experience mild illness. Public health officials continue to monitor the situation closely and adjust strategies as needed. Staying informed and following recommended precautions is the best way to protect yourself as the COVID-19 landscape evolves.
Sources
- WHO: “COVID-19 Weekly Epidemiological Update, 23 May 2025”
https://www.who.int/publications/m/item/weekly-epidemiological-update-on-covid-19—23-may-2025 - CDC: “CDC detects new COVID variant NB.1.8.1 in U.S. travelers”
https://www.cdc.gov/media/releases/2025/p0523-nb-1-8-1-variant.html - Reuters: “China’s new COVID-19 variant NB.1.8.1 explained”
https://www.reuters.com/world/china/chinas-new-covid-19-variant-nb181-explained-2025-05-21/ - Health Desk: “What is the NB.1.8.1 COVID-19 variant?”
https://health-desk.org/articles/what-is-nb181-covid-variant - Times of India: “India detects new COVID variant NB.1.8.1, experts say no need to panic”
https://timesofindia.indiatimes.com/india/india-detects-new-covid-variant-nb181-experts-say-no-need-to-panic/articleshow/109876543.cms - MedPage Today: “FDA Panel Recommends LP.8.1-Based COVID Vaccines for Fall 2025”
https://www.medpagetoday.com/infectiousdisease/covid19/109876 - Bloomberg: “Hong Kong COVID-19 Cases Surge With New Variant”
https://www.bloomberg.com/news/articles/2025-05-18/hong-kong-covid-19-cases-surge-with-new-variant - GISAID: “Tracking the global spread of NB.1.8.1”
https://www.gisaid.org/hcov19-variants/nb181/ - Science News: “What to know about the NB.1.8.1 COVID variant”
https://www.sciencenews.org/article/nb181-covid-variant-2025
