CDC Detects New COVID-19 Variant NB.1.8.1

The CDC’s airport screening program has identified several instances of the new COVID-19 variant NB.1.8.1, which is associated with a significant outbreak in China. Reports indicate that international travelers arriving at airports in California, Washington, Virginia, and the New York City area have tested positive for this variant.

Sequencing data published on the GISAID virus database reveals that these cases originate from travelers coming from various countries, including Japan, South Korea, France, Thailand, the Netherlands, Spain, Vietnam, China, and Taiwan. The travelers were tested between April 22 and May 12, according to information from Ginkgo Bioworks, the CDC’s testing partner.

Furthermore, health authorities in states like Ohio, Rhode Island, and Hawaii have reported additional cases of the NB.1.8.1 variant, separate from those discovered at airports. The earliest reports in California and Washington state date back to late March and early April.

Experts are closely monitoring this variant, which has now become prevalent in China and is escalating in parts of Asia. In Hong Kong, COVID-19 infection rates have surged, prompting a rise in emergency room visits and hospitalizations, marking the highest levels seen in over a year.

While Hong Kong officials assert there is no proof that the NB.1.8.1 variant causes more severe illness, they recommend that residents wear masks in crowded places or on public transportation, as the number of cases continues to rise. Similarly, Taiwan has reported increases in emergency room visits and serious cases, leading local health authorities to stockpile vaccines and antiviral treatments.

Preliminary research from China suggests that while the NB.1.8.1 variant may not evade the immune response more effectively than other circulating strains, it is better at attaching to human cells, potentially making it more transmissible.

Discussions on Vaccine Updates

The variant was a recurring topic during a recent meeting of the FDA’s external vaccine advisers, as they discussed potential updates for COVID-19 vaccines for the upcoming fall and winter seasons. Vaccines from the previous season targeted a variant related to JN.1, while early data indicated that switching to a new JN.1 variant—known as LP.8.1—could enhance protection against the NB.1.8.1 variant, according to representatives from Pfizer and Moderna.

Darin Edwards, who leads Moderna’s COVID-19 program, informed the committee that the LP.8.1 vaccine shows strong immune responses against LP.8.1 and effectively neutralizes other variants, including NB.1.8.1, which is prevalent in various Asian regions.

The advisory committee unanimously supported the idea that the next wave of vaccines should focus on a JN.1 variant, though opinions differed on how to implement this update. Some preferred to maintain last season’s vaccine formulation, while others advocated for targeting the LP.8.1 variant, which has been developed by Pfizer and Moderna.

“While we can’t predict exactly how the virus will evolve, the likelihood is that any strains causing outbreaks in the near future will come from those currently circulating. They won’t come from extinct strains,” noted Jerry Weir, director of the FDA’s division of viral products.

CDC and FDA officials shared that, currently, only one variant, named XFC, is displaying significant growth in the U.S. However, they warned that the virus’s evolution remains unpredictable, even as trends have stabilized into a somewhat predictable yearly pattern of surges—typically one in summer and another in winter.

This past winter saw only minor evolutionary changes in the virus rather than the large shifts experienced in earlier years. Although COVID-19 activity increased during winter, it remained considerably below prior peaks.

“This winter, we didn’t observe the substantial strain replacements that characterized the last few years. But I’m not saying we won’t see shifts soon,” remarked Natalie Thornburg from the CDC, emphasizing ongoing trends and observed patterns over the past five years.

Currently, COVID-19 levels have returned to low levels across the nation, as indicated by emergency room visit data and wastewater testing. Thornburg mentioned that the agency is analyzing seasonal patterns in the virus, hinting at a possibility of more predictable trends moving forward.