Winter Season Brings Norovirus and Other Maladies to Princeton
By Donald Gilpin
It’s flu season, along with rising case numbers of RSV and COVID-19, not to mention warnings of a bird flu threat. And if that’s not enough, U.S. health officials are now claiming it’s the worst season in many years for outbreaks of the norovirus, which is the leading cause of vomiting and diarrhea from acute gastroenteritis among people of all ages in the U.S.
Princeton Deputy Administrator/Health Officer Jeff Grosser reported that the Princeton Health Department has been monitoring the situation closely, investigating two separate norovirus outbreaks in a Princeton school and a day care last week, along with a few other localized outbreaks.
Cases of norovirus are common during the winter months, Grosser said, “especially in schools where the virus spreads quickly due to close contacts and shared surfaces.” The Princeton Health Department was able to identify 10 to 12 students/staff in each outbreak. “This demonstrates the quick spreading nature of norovirus,” Grosser added.
Penn Medicine Princeton Health Chief Medical Officer Dr. Craig Gronczewski has reported an increase in norovirus cases in the Penn Medicine Emergency Department, and he further notes that “beginning in September, regions throughout the country have seen an uptick in community cases of gastroenteritis especially in children and the elderly, some of which is caused by norovirus.”
In its newsletter last week the Municipality of Princeton reported a “notable increase in norovirus cases this winter season.”
As of January 10, there had been 30 reported outbreaks of norovirus in the state so far in 2025, following a spike in December 2024 when there were 70 outbreaks, according to the New Jersey Department of Health (NJDOH).
Each year there are about 2,500 reported norovirus outbreaks in the United States, the Centers for Disease Control and Prevention (CDC) reports, with most occurring from November to April. Individual cases of norovirus are not reportable.
The CDC goes on to note that norovirus causes on average 900 deaths per year, mostly among adults aged 65 and older; 109,000 hospitalizations; 465,000 emergency department visits, mostly young children; and 2,270,000 outpatient clinic visits annually, also mostly young children.
Gronczewski went on to explain, in a January 17 email, that norovirus is a seasonal virus that is highly contagious, with only a small amount able to cause an infection, and that it remains on surfaces and is comparatively resistant to household cleaners. It can transmit easily among close contacts for up to two weeks after an infection occurs.
The symptoms of the norovirus are usually brief, passing within 24 to 48 hours, but they can be harsh, often have an abrupt onset, and include chills, abdominal cramps, vomiting, and non-bloody diarrhea.
“Most people infected recover uneventfully — and just need some time and oral fluids,” Dr. Gronczewski wrote. “Staying hydrated is key to a swift recovery. However some people require emergency care and support at a hospital. Patients with severe illness may need IV hydration and electrolyte correction. Warning signs include high fever with shaking chills, severe abdominal pain, and bloody diarrhea. These symptoms warrant immediate medical attention.”
To avoid norovirus and prevent its spread, Grosser recommended frequent hand washing with soap and water for at least 20 seconds, avoiding contact with sick individuals, and disinfecting high-touch surfaces like doorknobs and countertops with a bleach solution or disinfectant that’s effective against norovirus.
“Given that norovirus is very contagious, it’s critical that anyone who feels sick stays home for at least 48 hours after symptoms subside to avoid spreading the virus to others,” Grosser added.
The NJDOH emphasizes the risk of dehydration for people infected with norovirus. “It is important to drink liquids to replace fluid lost when vomiting or diarrhea,” states the NJDOH website.“With more than 20 million cases of gastroenteritis caused by norovirus every year, that means that 1 in every 15 Americans will become ill from norovirus each year.” About 100 outbreaks are reported in New Jersey each year.
Noroviruses can spread quickly in crowded, closed places like long-term care facilities, daycare centers, schools, hotels, summer camps, hospitals, restaurants, and cruise ships —places where people often eat food that is prepared and handled by others, according to NJDOH.
Leafy greens and ready-to-eat foods are most commonly involved in norovirus outbreaks. There is no vaccine for norovirus infection and no drug to treat people who get sick from the virus.
Other Health Concerns
Grosser went on to point out other winter health concerns that the Princeton Health Department has been focusing on. He cited a number of flu cases in the area and urged all residents to practice good hygiene and to get their flu shots if they haven’t already.
“Cold weather and icy conditions also present a higher risk of slips and falls,” he added, “especially for older adults, so it’s important to be cautious heading outdoors in freezing temperatures or after a snowfall.”
In addition to physical health concerns, Grosser also emphasized the potential impact of winter on mental health. “Seasonal affective disorder, or the ‘winter blues,’ can affect many people, so we encourage residents to stay active, get outside when possible, and reach out to mental health services if they’re feeling overwhelmed.”
He continued, “The municipality houses Princeton Integrated Behavioral Health at Monument Hall. They offer a range of mental health services to anyone 12 years and older. Medicaid and all insurance plans are accepted, along with those with no insurance.”
Grosser stressed the importance of prevention and staying informed. “We’re committed to providing the community with up-to-date information and ensuring that resources are available to help manage these health challenges,” he said.