JN.1 now accounts for 44 percent of US cases, according to new data from the Centers for Disease Control and Prevention (CDC) released on Friday, Dec. 22.
Just a week earlier, JN.1 had made up 21.4 percent of US cases in previously reported CDC data.
In the Northeast, JN.1 is even more widespread, accounting for more than 56 percent of new COVID cases, the CDC says.
The World Health Organization declared JN.1 to be "a variant of interest" on Tuesday, Dec. 19, saying "its prevalence has been rapidly increasing globally."
"Based on its genetic features, JN.1 may possess some antigenic advantage evading previous immunity," the WHO said. "With the limited data at this stage, the available evidence on JN.1 does not suggest additional public health risks relative to the other currently circulating Omicron descendent lineages.
"While there is a rapid increase in JN.1 infections, and likely increase in cases, available limited evidence does not suggest that the associated disease severity is higher as compared to other circulating variants."
According to epidemiologists, JN.1 symptoms so far have been similar to those of Omicron and its subvariants, often including sore throat and congestion.
"In general, symptoms of COVID-19 tend to be similar across variants," the CDC said in a statement earlier this month.
"The types of symptoms and how severe they are usually depend more on a person’s immunity and overall health rather than which variant causes the infection."
JN.1 was first identified this past August.
The HV.1 Omicron subvariant, also identified late in the summer, is the No. 2 strain in the US, accounting for 22 percent of cases in the country.
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