Norovirus Cases Are Surging, CDC Says: What To Know In CA

CALIFORNIA — Norovirus is quickly spreading, exceeding past seasonal averages for outbreaks of the wretched stomach bug that sickens millions of people every year.

Norovirus outbreaks spiked to 91 for the week ended Dec. 5, up from 69 in the last week in November, according to the latest data available from the U.S. Centers for Disease Control and Prevention. In the past few years, a maximum of 65 outbreaks have been reported during the first week in December, the agency says.

Here in California, a spike in cases may be attributed to contaminated oysters. The Food and Drug Administration advises that S&M Shellfish Co. of San Francisco issued a recall for certain oysters harvested from British Columbia, Canada "due to a norovirus outbreak." Though the oysters were harvested in Canada, they were distributed by the San Francisco company.

The oysters were sold as Fanny Bay, Buckley Bay and Royal Miyagi oysters that were harvested between Dec. 1 and Dec. 9.

The California Department of Public Health said that as of Dec. 12, "57 confirmed and probable cases of norovirus have been reported among people who ate raw oysters from British Columbia while dining at several restaurants in California."

The virus is considered "highly contagious," and the health department notes that even if you did not eat the oysters, you can catch norovirus simply from touching something that a person with norovirus has touched.

It's also important to remember that "anyone can get norovirus, even if they’ve had it before," according to the CDPH.

How does this year compare to previous years here in California? The CDPH prepared a list of laboratory-confirmed norovirus outbreaks in the state from January to November each year from 2019 to 2024.

• 2019: 76
• 2020: 12 (The COVID pandemic likely made this year artificially low)
• 2021: 45
• 2022: 56
• 2023: 73
• 2024: 55 (Through Nov. 30. As noted above, the outbreak linked to oysters is expected to boost this number as suspected cases are laboratory confirmed.)

The department told Patch in an email, "We may not have updates until after the holiday." The CDPH offers resources pertaining to norovirus here.

The CDC says the 91 reported outbreaks are likely an undercount. State, local and territorial health departments aren’t required to report individual norovirus cases to the agency. Also, symptoms — violent diarrhea and vomiting — last for one to three days, and most people don’t seek medical treatment, the agency says.

Illnesses are going up across the nation.

Minnesota had 40 norovirus outbreaks in the weeks leading up to Christmas, state public health officials said in a Dec. 23 news release. In California, dozens were sickened earlier this month at an event in Los Angeles celebrating the city’s top restaurants, the county’s Department of Public Health confirmed. And last week, the Food and Drug Administration advised California restaurants and retailers not to serve or sell and consumers not to eat certain oysters contaminated with norovirus.

Norovirus causes 58 percent of foodborne illnesses in the United States, according to the CDC. Annually, between 19 million and 21 million norovirus illnesses are reported to the CDC, including 109,000 hospitalizations and 900 deaths.

Outbreaks are common in restaurants and catered events, schools and daycare centers, health care facilities, cruise ships, jails, and any other place where people are close together.

Norovirus is highly contagious and is spread through direct contact with someone who is sick, sharing food or utensils with them, touching surfaces contaminated with the virus and then touching their face or mouth, or by consuming contaminated foods or liquids.

Symptoms usually come on within 12 or 48 hours of becoming infected. The most common symptoms are diarrhea, vomiting, nausea and stomach pain, but also may include fever, headache and body aches.

There’s no antiviral medication for norovirus. The most important thing is to make sure people who have it get plenty of liquids. People who have norovirus may vomit or have diarrhea several times a day and are at risk of dehydration — especially in young children, older adults and people with other illnesses.

Symptoms of dehydration include:

• Decreased urination
• Dry mouth and throat
• Feeling dizzy when standing up
• Crying with few or no tears
• Unusual sleepiness or fussiness

The best way to prevent norovirus is to wash hands in hot, soapy water for 20 seconds after using the toilet, changing diapers and before eating, preparing or handling food. Hand sanitizer isn’t particularly effective at controlling the spread of the virus.

Also, thoroughly wash fruits and vegetables, and to cook shellfish to an internal temperature of 145 degrees Fahrenheit to prevent norovirus contamination.

SEE ALSO: Dozens Sickened After Eating Raw Oysters At LA Times Food Event: Reports