The rapid growth of the coronavirus subvariant JN.1 during the holiday season could fuel winter waves of illness in the United States and beyond, public health authorities warn.
JN.1 caused nearly half of new U.S. coronavirus infections in the two weeks leading up to Christmas, the Centers for Disease Control and Prevention estimates. The World Health Organization on Dec. 19 declared JN.1 a variant of interest “due to its rapidly increasing spread,” from 3 percent of global cases in early November to 27.1 percent a month later.
The timing concerns experts because JN.1 appears to be spreading efficiently in a period when coronavirus usually surges as people travel for the holidays and stay indoors. Covid hospitalizations and coronavirus wastewater levels are rising in the United States.
Coronavirus is constantly evolving into forms that are more transmissible or more adept at infecting people who were vaccinated or previously infected. Those attributes help variants outcompete others in circulation and fuel waves of infection. But the scenario scientists have dreaded has yet to materialize in the last two years: a highly contagious variant far deadlier than the ones before it.