As of May 2025, a new COVID-19 variant, known as NB.1.8.1, is making headlines across the globe. This variant, which is a subvariant of the Omicron lineage JN.1, has been linked to recent surges in cases throughout Asia and has now been confirmed in the United States. It's crucial to understand the implications of this variant and how it may impact public health.
NB.1.8.1 is a descendant of the JN.1 variant, which itself is part of the broader Omicron lineage. First identified in China, this variant has quickly become the dominant strain in the region, contributing to a significant increase in COVID-19 cases. Its presence has also been noted in other Asian countries, including Singapore and Hong Kong, and it was recently detected in the United States through airport screening programs.
The World Health Organization (WHO) has designated NB.1.8.1 as a SARS-CoV-2 variant under monitoring (VUM), with its proportions increasing globally. According to a press release, this variant has been under surveillance since it was first sampled on January 22, 2025, and was officially categorized as a VUM on May 23, 2025.
The symptoms of NB.1.8.1 closely mirror those of previous Omicron variants. Commonly reported symptoms include:
Sore throat Fatigue Mild cough Fever Muscle aches CongestionSome individuals have also reported experiencing persistent low-grade hyperthermia, which is characterized by a body temperature that remains elevated due to failed thermoregulation, differing from a typical fever. Other symptoms may include headaches, nausea, loss of appetite, and gastrointestinal issues.
Initial data indicates that NB.1.8.1 has a higher transmissibility rate compared to several earlier variants. This variant appears to have an enhanced ability to bind to human cells, which may lead to increased infection rates. It has been detected in travelers arriving at major U.S. airports, including those in California, Washington, Virginia, and New York, highlighting the necessity for continued surveillance and robust public health measures.
Despite a rise in cases and hospitalizations in certain regions where NB.1.8.1 is prevalent, current data suggests that this variant does not result in more severe illness compared to other variants in circulation, according to the WHO. In India, for instance, a mild increase in COVID-19 cases is being observed, primarily due to the emergence of new Omicron subvariants like JN.1. Dr. Divya K S, a Consultant Infectious Disease specialist at Apollo Hospitals, Sheshadripuram, notes that as infections become endemic, periodic surges are common. However, the current numbers are not alarming.
Dr. Divya emphasizes that factors such as waning immunity, decreased vaccination rates, increased international travel, and the emergence of new variants contribute to these fluctuations. Most infections reported so far remain mild, with symptoms including fever, sore throat, and fatigue. While there is no immediate cause for alarm, maintaining vigilance is advisable, particularly for vulnerable populations such as the elderly, immunocompromised individuals, and those with chronic conditions like chronic kidney disease, diabetes mellitus, and COPD.
In conclusion, as we continue to navigate the challenges posed by COVID-19 and its variants, staying informed about developments like NB.1.8.1 is essential for public health and safety.
