Archive · 28 May 2025
Highly Contagious COVID Variant, NB.1.81, Detected in US
A new COVID-19 variant, NB.1.81, is spreading in the US after causing hospitalizations in China.
It spreads quickly and might not be fully stopped by vaccines.
Symptoms are typical COVID symptoms.
The CDC is adjusting guidance and some experts are concerned about its ability to spread faster, leading to more cases if not managed.
Officials in China and Hong Kong downplay the threat, while experts urge people to take the situation seriously.
A new, highly contagious COVID-19 variant, NB.1.81, has been detected in the US.
The variant was first found in international travelers and has spread to several states.
NB.1.81 became the dominant strain in China, leading to a surge in hospitalizations.
Experts express concern about the variant's potential to evade vaccine protection.
Health officials warn NB.1.81 should be taken seriously due to early signs of vaccine mismatch.
- Who
- Public health officials, international travelers, infected individuals, and residents of affected regions.
- What
- The spread of the highly contagious COVID-19 variant NB.1.81.
- When
- Cases have been found between late March and early April, and more cases have been identified since.
- Where
- United States, including New York City, California, Washington State, Virginia, Ohio, Rhode Island, and Hawaii. Also spreading in China and Hong Kong.
- Why
- Increased transmissibility and potential evasion of existing vaccine protection.
US/Expert Perspective
Hong Kong/China perspective
Severity
US/Expert Perspective
The variant’s rapid spread may foreshadow a new wave of infections in the US. Experts urge caution.
Hong Kong/China perspective
NB.1.81 is not more dangerous than previous strains.
- Variant Name
- NB.1.81
- Common Symptoms
- Sore throat, cough, fatigue, and fever
- Affected Regions
- China, Hong Kong, US, Japan, South Korea, France, Thailand, Vietnam, Netherlands
- Expert Concern
- Early signs of vaccine mismatch
- Detection Timeline
- US, from late March to early April
Sources
New COVID variant NB.1.8.1 is a VUM: What does it say about its severity, symptoms and transmission rate?
Do you need Covid vaccine again? Doctors weigh in amid rising cases
COVID comeback? US detects new variant linked to China's latest surge
COVID-19 resurges: Early symptoms and severity
