Norovirus: Cases Surge – Symptoms, Prevention & What to Do

Cases of norovirus, often called the “winter vomiting bug,” are rising across the United States, with a more than 50% increase reported in the past week. This surge is also putting additional strain on healthcare systems, as outbreaks are occurring in hospitals.

What is Norovirus?

Norovirus is a highly contagious virus that causes gastroenteritis – inflammation of the stomach and intestines. The illness is characterized by the sudden onset of severe vomiting and diarrhea. While unpleasant for most, norovirus can be particularly serious for older adults, young children, and individuals with underlying health conditions.

Although commonly referred to as the “stomach flu,” norovirus is unrelated to influenza (the flu), and the flu shot will not protect against it. It’s a distinct virus that causes acute gastroenteritis, leading to symptoms like cramps, diarrhea, and vomiting.

How Widespread is the Current Surge?

To date this winter, a total of 676 cases of norovirus have been reported. However, the most recent data, ending February 7th, shows a significant increase, with 86 cases notified – a rise of over 50% compared to the previous seven days. The majority of those affected are between the ages of 16 and 64, with a median age of 46.

Nationally, norovirus levels are currently considered “high,” according to WastewaterSCAN, which monitors diseases through municipal wastewater systems. Concentrations are up 45% since November, with a significant upward trend in the last three weeks. Levels are particularly elevated in the Midwest and Northeast.

The current uptick appears to be driven by a newer variant of the virus, which also fueled a harsh 2024-2025 season. Last winter, norovirus outbreaks surged to decade-high levels.

What Should I Do If I Contract Norovirus?

For most people, norovirus infection is self-limiting and resolves without specific medical treatment. Dr. Eimear Brannigan, Health Service Executive national clinical lead for antimicrobial resistance and infection control, emphasizes that “drinking plenty of fluids is usually all that is needed.”

However, it’s important to be aware that norovirus can lead to dehydration, especially in vulnerable populations. Seek medical attention if you experience signs of dehydration, such as decreased urination, dizziness, or extreme thirst.

How Can I Prevent the Spread of Infection?

Norovirus is exceptionally contagious. Very few viral particles are needed to cause infection, making prevention crucial. Several steps can be taken to minimize the risk of spreading or contracting the virus.

Individuals experiencing symptoms should stay home from work or school for at least 48 hours after their symptoms have completely subsided. Avoid visiting hospitals or care homes, and refrain from socializing during illness and for 48 hours afterward.

Frequent and thorough handwashing with soap and water is paramount. Hand sanitizers are less effective against norovirus. Disinfect surfaces and objects that may be contaminated, and wash clothing and bedding separately in hot water to kill the virus. Avoid sharing towels and face cloths within the household.

Because norovirus spreads through contaminated food, water, and surfaces, careful food handling practices are essential. Heat food to sizzling temperatures and ensure thorough cooking.

When Should I Seek Medical Attention?

If you experience vomiting or diarrhea, the Health Service Executive advises against visiting emergency departments unless absolutely necessary. Instead, consult with a pharmacist or primary care physician by phone to prevent further spread of infection.

“It is important not to bring norovirus into health or care settings; if staff become infected, this can lead to disruption of service or closure of premises. If vulnerable patients become infected, the consequences can be very serious,” the organization states.

However, if you are severely unwell or experiencing signs of dehydration, do not hesitate to seek emergency medical care. Inform reception staff immediately of your symptoms so they can implement appropriate precautions to minimize the risk of transmission.

Understanding Norovirus Transmission

Unlike respiratory viruses like influenza and COVID-19, norovirus is not spread through coughing or sneezing. Masking and improved ventilation are therefore not effective preventative measures. The primary mode of transmission is through contact with contaminated surfaces, food, or water.

Norovirus is the leading cause of gastroenteritis and the most common cause of food poisoning in the United States. Each year, it causes an estimated 19–21 million illnesses, 109,000 hospitalizations, and 900 deaths, according to the U.S. Centers for Disease Control and Prevention.