Worst of norovirus surge has likely passed, county health officials say

Santa Cruz County experienced its peak of norovirus infections in October and November, weeks before the highly contagious stomach bug began surging across much of the country, public health officials say.

While the virus remains present in the community, Dr. Lisa Hernandez, the county health officer, said she is “very hopeful” that the peak is behind us, adding that local health care facilities have managed the outbreak — and the usual winter rise in respiratory illnesses — without significant strain.

Wastewater data showed a rise in norovirus circulating in late October and early November, somewhat earlier than the spike that many other parts of the United States observed in December. Public health officials first saw the virus spiking in wastewater from South County in October and November, while other parts of the county saw higher levels of illness in mid-December. 

That wastewater data is now “showing signs of decrease,” Hernandez said. 

“I would say, generally, we’re OK,” she said, “We’re still a little bit elevated, but I’m hoping in the next week or so we will see some more reductions in the wastewater. I am very hopeful that the wave has passed us and that we don’t see it again.”

Norovirus infections are characterized by severe vomiting, diarrhea and stomach pain — symptoms that usually begin 12 to 48 hours after exposure to the virus. The symptoms typically last up to three days. While most people recover without needing treatment, severe cases can lead to dangerous dehydration and require medical attention. That occurs most often in young children, older adults and those with underlying medical conditions.

Norovirus infections spread with ease in close and crowded environments, like nursing homes, health care facilities, schools and cruise ships. The virus’ resiliency can make it particularly difficult to quell an outbreak, Hernandez noted. While a virus like COVID does not survive long on surfaces, norovirus can linger for much longer, opening the door for more infections via contaminated surfaces.

A county health alert from early November said that from late October to early November, there were 93 cases of norovirus reported at a South County school, and another 33 additional gastrointestinal illness cases reported at a workplace with no known connection to the school. However, Hernandez said county public health officials have not received any further reports of outbreaks of norovirus in institutional settings like health care facilities, schools and nursing homes. Such institutions are required to report outbreaks to public health officials. 

Hernandez added that Santa Cruz County has fared well with the usual suspects — COVID, respiratory syncytial virus (RSV) and flu — so far this year, following consecutive winters that raised concerns about a potential “tripledemic” of the three illnesses. In particular, 2022 saw record numbers of emergency room visits during December as flu and RSV surged. She said that there is COVID transmission across the county, but that it has largely plateaued. She added that the county’s hospitalization prediction model shows that hospitalizations could increase later in January, but only slightly.

The county’s COVID dashboard shows the reproductive level — a figure that represents the average number of secondary COVID cases caused by a primary case, calculated over a five-day moving average — hovering just over 1, which means that the disease is actively spreading. However, it has been at its current level since early-to-mid November. There were only three people countywide in the hospital with COVID as of Dec. 31, and wastewater prevalence at the end of 2024 was far beneath the Centers for Disease Control and Prevention’s threshold for “moderate risk,” which is 200 or more new cases per week per 100,000 people.

“We’ve had hospitalizations, but not to the point where the facilities are verbalizing any sort of stress that I worry about every year, and I’m sure they do too,” said Hernandez.

The county is not out of the woods yet, Hernandez said, as flu cases tend to spike in January and February, but she does not think that the three respiratory viruses will all spike at the same time: “I can never guarantee that, but it looks like we might not see that this year.”

The public will soon be able to take a better look at the state of COVID, RSV and flu in the county throughout the year. Hernandez said the county’s public health department is working on a new dashboard that provides data on hospitalizations and deaths attributed to flu and “potentially RSV” to pair with its COVID dashboard. 

The COVID dashboard has been public since the pandemic began in 2020 and features the current reproductive number, wastewater prevalence and hospitalizations. Hernandez also said the Santa Cruz County Health Services Agency is working to see what kind of vaccination data it can include as well, like uptake rate for each jab.

“Because all of the vaccination data has to come from the California Immunization Registry, it’s not going to be as easy as it was in the past for COVID,” she said. “But ideally, it would be great to have vaccination information for all three.”

Hernandez said there is no specific launch date for the new dashboard, but that it is likely to be completed in a matter of months. The goal is to update the data throughout the year, as public health officials have done with COVID since the pandemic, but the agency hasn’t made a final decision yet.

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