the global health agency has announced.
JN.1 was previously grouped with its relative, BA.2.86, but has increased so much in the past 4 weeks that the WHO moved it to standalone status, according to a summary published by the agency. The prevalence of JN.1 worldwide jumped from 3% for the week ending November 5 to 27% for the week ending December 3. During that same period, JN.1 rose from 1% to 66% of cases in the Western Pacific, which stretches across 37 countries, from China and Mongolia to Australia and New Zealand.
In the United States, JN.1 has been increasing rapidly. The variant accounted for an estimated 21% of cases for the 2-week period ending December 9, up from 8% during the 2 weeks prior.
SARS-CoV-2 is the virus that causes COVID, and like other viruses, it evolves over time, sometimes changing how the virus affects people or how well existing treatments and vaccines work against it.
The WHO and CDC have said the current COVID vaccine appears to protect people against severe symptoms due to JN.1, and the WHO called the rising variant’s public health risk “low.”
“As we observe the rise of the JN.1 variant, it’s important to note that while it may be spreading more widely, there is currently no significant evidence suggesting it is more severe or that it poses a substantial public health risk,” John Brownstein, PhD, chief innovation officer at Boston Children’s Hospital, told ABC News.
In its recent risk analysis, the WHO did acknowledge that it’s not certain whether JN.1 has a higher risk of evading immunity or causing more severe symptoms than other strains. The WHO advised countries to further study how much JN.1 can evade existing antibodies and whether the variant results in more severe disease.
The latest CDC data show that 11% of COVID tests reported to the agency are positive, and 23,432 people were hospitalized with severe symptoms within a 7-day period. The CDC urgently asked people to get vaccinated against respiratory illnesses like the flu and COVID-19 ahead of the holidays as cases rise nationwide.
“Getting vaccinated now can help prevent hospitalizations and save lives,” the agency advised.
A version of this article originally appeared on WebMD.com.