Notorious 'winter vomiting bug' rising in California. A new norovirus strain could make it worse

This is read by an automated voice.Please report any issues or inconsistencies here.

The dreaded norovirus — the “vomiting bug” that often causes stomach flu symptoms — is climbing again in California, and doctors warn that a new subvariant could make even more people sick this season.In L.A.

County, concentrations of norovirus are already on the rise in wastewater, indicating increased circulation of the disease, the local Department of Public Health told the Los Angeles Times.Norovirus levels are increasing across California, and the rise is especially notable in the San Francisco Bay Area and L.A., according to the California Department of Public Health.And the rate at which norovirus tests are confirming infection is rising nationally and in the Western U.S.

For the week that ended Nov.22, the test positivity rate nationally was 11.69%, up from 8.66% two months earlier.

In the West, it was even worse: 14.08%, up from 9.59%, according to the U.S.Centers for Disease Control and Prevention.

Norovirus is extraordinarily contagious, and is America’s leading cause of vomiting and diarrhea, according to the CDC.Outbreaks typically happen in the cooler months between November and April.

California The number of national norovirus outbreaks was the highest seen in December since at least 2012.Experts suggest increased hand-washing to avoid catching the ultra-contagious stomach bug.Clouding the picture is the recent emergence of a new norovirus strain — GII.17.

Such a development can result in 50% more norovirus illness than typical, the CDC says.“If your immune system isn’t used to something that comes around, a lot of people get infected,” said Dr.

Peter Chin-Hong, an infectious diseases expert at UC San Francisco.During the 2024-25 winter season, GII.17 overthrew the previous dominant norovirus strain, GII.4, that had been responsible for more than half of national norovirus outbreaks over the preceding decade.

The ancestor of the GII.17 st...