As the world continues to grapple with the ongoing effects of COVID-19, particularly the surge in cases that has led to approximately 350 deaths per week in the U.S. over the past month, a new variant of the SARS-CoV-2 virus has emerged, dubbed the NB.1.8.1 variant. This variant is currently causing significant spikes in cases in regions such as China, Hong Kong, and Taiwan, and it is beginning to spread within the United States as well.
While previous variants like XEC and LF.7 seem to have peaked, the LP.8.1 variant is presently the dominant strain in North America, parts of South America, and across Europe and South Africa. First identified in September 2024, LP.8.1 has been the primary variant affecting global health through the past winter.
Spring 2025 has seen the rise of the XFG variant, a recombinant of the LF.7 and LP.8.1.2 variants, first detected in Quebec, Canada. By the end of April, XFG constituted about 10% of all sequenced SARS-CoV-2 samples across North America and Europe. As these variants compete for dominance, the NB.1.8.1 variant is emerging as a significant player, particularly in Asia.
The NB.1.8.1 variant has shown a capacity to connect to human cells more readily than XFG, while XFG may evade immune protection more effectively. This dynamic competition suggests that the spread and dominance of these variants will vary based on the population's prior exposure and vaccination status.
In regions like China and Hong Kong, the NB.1.8.1 variant has triggered a notable increase in emergency room visits and hospitalizations, prompting health authorities to recommend mask-wearing in crowded public areas. Taiwanese health officials are proactively stockpiling vaccines and antiviral treatments to combat the anticipated wave driven by this variant. While there is no definitive evidence suggesting that NB.1.8.1 causes more severe health outcomes than its predecessors, ongoing studies are crucial for understanding its full impact.
Despite the emergence of the NB.1.8.1 variant, the U.S. lacks a comprehensive surveillance system for SARS-CoV-2, which complicates the tracking of new variants. The Centers for Disease Control and Prevention (CDC) has detected cases of NB.1.8.1 through airport screenings in California, Washington, Virginia, and New York City, with additional cases reported in states like Ohio, Rhode Island, and Hawaii. It is evident that NB.1.8.1 has established a foothold in the U.S.
The vaccines currently available in the U.S. target earlier variants of the virus, such as the spike proteins from previous strains. Discussions are underway regarding potential updates for this fall, with options including maintaining the existing vaccines or adapting them to target newer variants like LP.8.1, which is more closely related to NB.1.8.1. Enhanced vaccines targeting LP.8.1 could provide better protection against the emerging variant.
Currently, the U.S. response to the NB.1.8.1 variant appears lackluster. Politicization of COVID-19 measures has hindered effective public health responses. The FDA is considering limiting vaccine approvals to older adults and those with pre-existing conditions, which raises concerns about increased vulnerability among the general population. As the U.S. continues to navigate the complexities of the pandemic, it remains crucial to monitor the spread of variants like NB.1.8.1 and adapt public health strategies accordingly.
In summary, while the NB.1.8.1 variant presents new challenges, ongoing surveillance, vaccination strategies, and public health measures will be essential in managing its impact and ensuring community health in the face of evolving threats from COVID-19 variants.
