New Covid Variant NB.1.8.1 detected. Credit: Anna Shvets, Pexels
A new COVID-19 variant, NB.1.8.1, linked to a surge in cases across China and parts of Asia, has now been detected in the United States, with confirmed cases among international travellers arriving between late April and mid-May.
New Covid Variant NB.1.8.1 found in US airports
According to data from Ginkgo Bioworks, the testing partner of the US Centers for Disease Control and Prevention (CDC), cases of the NB.1.8.1 variant were identified in travellers at airports in:
- California
- Washington state
- Virginia
- New York City
Travellers infected with new Covid variant came from Asia and parts of Europe, including Spain
Sequencing records uploaded to the Global Initiative on Sharing All Influenza Data (GISAID) confirm that the infected travellers arrived from a wide range of countries, including China, Taiwan, Japan, South Korea, Thailand, Vietnam, France, Spain, and the Netherlands, between April 22 and May 12.
Separate from the airport screenings, cases of NB.1.8.1 have also been reported by local health authorities in Ohio, Rhode Island, and Hawaii, with earlier detections in California and Washington state dating back to late March and early April.
NB.1.8.1 has become the dominant variant in China and is contributing to the highest COVID-19 levels in over a year in Hong Kong, according to local health authorities. Hong Kong officials have reported:
- A “significant increase” in emergency room visits and hospitalisations
- Calls for the public to wear masks in crowded areas and on public transport
Similarly, Taiwan has seen a rise in severe cases and deaths, prompting officials to stockpile vaccines and antiviral treatments in anticipation of further spread.
Should we be worried about the new Covid variant NB.1.8.1?
So far, the variant does not appear to cause more severe illness than previous strains. However, preliminary studies from Chinese researchers suggest NB.1.8.1 has a greater ability to bind to human cells, which could make it more transmissible.
It does not significantly evade immunity, meaning vaccines and past infections may still offer protection.
US prepares for next Covid vaccine update
The potential impact of NB.1.8.1 was discussed during a US Food and Drug Administration (FDA) advisory meeting on Thursday, May 22, 2025, where officials debated how best to update COVID-19 vaccines for the autumn/winter season.
Pfizer and Moderna data indicated that their candidate vaccines targeting LP.8.1, another JN.1 descendant, also provide protection against NB.1.8.1.
Although there was debate over whether to update the vaccines or stick with last season’s version, the panel unanimously agreed to target a JN.1-lineage strain for future vaccine updates – the type that’s currently dominant. This was reported by CBS News.
The CDC reported that overall COVID-19 rates in the US are currently low, with cases and hospital visits down nationwide.
“After five years now, we are seeing very distinct patterns,” said Natalie Thornburg, acting chief of the CDC’s respiratory virus lab division, adding that COVID-19 may now follow a more seasonal pattern, with two expected waves per year – one in summer and another in winter.
However, she cautioned that while current trends show only minor genetic shifts in the virus, a significant change could still occur.
Was Covid-19 leaked from a lab?
As new variants like NB.1.8.1 continue to emerge and spread globally, some experts and officials are also revisiting the origin of the Covid-19 virus. Earlier this year, the CIA suggested that COVID-19 may have been leaked from a laboratory, a theory that continues to fuel international debate. Even the White House published an online page titled “Lab Leak: The True Origins of Covid-19”.
View all world news.
