An alarming surge in norovirus cases is sweeping across the United States this winter, according to data from the Centers for Disease Control and Prevention (CDC). The virus, often called the stomach flu, has spurred outbreaks in schools, nursing homes, cruise ships, and other close-contact environments, raising public health concerns as the peak season continues.
The CDC reported 91 outbreaks during the week of December 5, a sharp increase from 69 outbreaks recorded the previous week. This marks the highest number of reported incidents for this time of year since 2021, with cases surpassing previous records for early December. Minnesota health officials noted that cases in their state have doubled compared to average December levels, echoing the national trend.
Norovirus is the leading cause of foodborne illness in the U.S., responsible for 58% of such infections annually, according to the CDC. Highly contagious, it spreads through direct contact with infected individuals, contaminated food or water, or surfaces. Symptoms include sudden vomiting, diarrhea, nausea, and stomach cramps, typically appearing 12 to 48 hours after exposure.
The virus has proven particularly disruptive aboard cruise ships, which have seen an unprecedented number of outbreaks this month. More than 80 passengers and crew on a Holland America Line cruise departing Fort Lauderdale on December 8 reported norovirus symptoms. Similarly, outbreaks occurred on Princess Cruises' Ruby Princess and Holland America's Zuiderdam earlier in December, impacting hundreds of travelers. December has become the most active month for cruise-related norovirus cases in 2024, with 14 incidents recorded this year.
On land, foodborne outbreaks have also drawn attention. At a Los Angeles event earlier this month, over 80 attendees fell ill after consuming oysters linked to a norovirus contamination. The U.S. Food and Drug Administration (FDA) subsequently recalled oysters from British Columbia, warning consumers of potential exposure to the virus.
Dr. Leana Wen, former Baltimore health commissioner, emphasized prevention measures during an appearance on CBS's "Face the Nation." "Wash your hands, really well, especially if you're going to buffets," Wen advised. "Don't prepare food if you're experiencing vomiting, diarrhea, or stomach cramps to avoid spreading it to others."
The CDC reports that the virus disproportionately affects vulnerable populations, particularly young children and seniors over 65. Dehydration from severe vomiting and diarrhea remains a primary concern, with symptoms such as reduced urination, dizziness, and dry mouth signaling the need for medical attention. Each year, norovirus leads to an estimated 900 deaths and 109,000 hospitalizations in the U.S., mostly among older adults and individuals with weakened immune systems.
Outbreaks often peak between November and April, and new strains of the virus can drive significant increases in cases. This season's uptick has been attributed to a more infectious strain, though the virus's rapid transmission in communal settings is also a factor.
Efforts to combat the virus rely heavily on hygiene. Rigorous handwashing with soap and water for at least 20 seconds is the most effective defense. Alcohol-based hand sanitizers are less effective against norovirus, according to health experts. Surfaces should be disinfected with household cleaners, and contaminated laundry should be washed in hot water to reduce the risk of spreading the virus.
While norovirus infections are typically short-lived, lasting one to three days, their sudden onset and severe symptoms make them particularly distressing. Health officials recommend staying hydrated with oral rehydration solutions like Pedialyte and avoiding caffeinated or alcoholic beverages, which can exacerbate dehydration.
Despite the increase in cases, public health officials remain focused on containment and education. With nearly 2,500 norovirus outbreaks reported annually in the U.S., this seasonal spike underscores the importance of preventive measures and prompt response to minimize its impact.
As the holiday season continues and people gather in close quarters, vigilance against norovirus is critical to reducing its spread and protecting public health.