Norovirus surge in the United States: Symptoms, transmission, who is at risk, preventive measures

An increase in norovirus outbreaks has been reported in parts of the United States this winter, according to the US Centers for Disease Control and Prevention (CDC). Cases of the highly contagious stomach bug have been on the rise since early December, with a noticeable increase in the number of outbreaks compared to previous years.

Outbreaks on the rise: CDC data

During the week of December 5, the CDC reported 91 outbreaks of norovirus, a significant increase from the 69 outbreaks recorded the previous week in late November. Historically, the first week of December sees no more than 65 outbreaks, underscoring the recent spike in cases. This increase signals a potential concern as the virus spreads across the country.

Notorious for causing sudden vomiting and diarrhea, norovirus is highly contagious and often spreads quickly in environments where people are around. These outbreaks are often observed on cruise ships in congregate settings such as nursing homes, schools and other facilities where large numbers of people interact.

Understanding Norovirus: Symptoms and Spread

Norovirus is the leading cause of foodborne illness in the United States, responsible for 58% of food-related infections each year, according to CDC data. The virus is highly contagious, with as few as 10 viral particles capable of causing disease. On average, about 2,500 norovirus outbreaks are reported annually in the United States, with peak activity from November to April.

The primary symptoms of norovirus include sudden vomiting, diarrhea, nausea, abdominal pain, body aches, headache, and fever. The illness typically begins 12 to 48 hours after exposure to the virus and lasts 1 to 3 days, with most people making a full recovery without the need for medical treatment. However, the virus leads to approximately 900 deaths and 109,000 hospitalizations each year, primarily among vulnerable populations such as older adults (65 years and older).

Transmission: How Norovirus Spreads

Norovirus spreads easily through several routes. The most common method of transmission is from person to person, especially when infected people share food, utensils or come into close contact with others. Outbreaks can also occur through contaminated food, water or surfaces that have been exposed to the virus.

Norovirus outbreaks are especially common in settings where people are in close proximity, such as cruise ships, long-term care facilities, schools and prisons. The virus can survive on surfaces for days, making proper sanitation and hygiene essential to prevent its spread.

Who is at risk?

Norovirus can affect anyone, but certain groups are more vulnerable to severe illness. Young children, the elderly, and people with weakened immune systems are at higher risk of complications, including dehydration caused by vomiting and diarrhea. Dehydration is the primary concern for those infected, as it can lead to serious health problems, especially in young children and older adults.

What to do if you are sick: Managing symptoms

Although there is no specific medication to treat norovirus, people affected by the virus should focus on rehydration to prevent dehydration. It is recommended to drink fluids such as water, oral rehydration solutions and clear broths, avoid coffee, tea and alcohol as these can worsen dehydration.

In the event of severe dehydration, individuals should seek immediate medical attention. Symptoms of dehydration include a decrease in urination, dry mouth, dizziness and fatigue. Children may exhibit unusual sleepiness, fussiness, and may cry with few or no tears, signaling dehydration.

Preventive measures: How to protect yourself

Prevention of the spread of norovirus depends primarily on good hygiene and sanitation. The CDC recommends frequent and thorough hand washing with soap and warm water for at least 20 seconds before meals and after using the restroom. Hand sanitizers may not be as effective against norovirus, making hand washing the most reliable prevention method.

Additionally, disinfecting surfaces with household disinfectants, especially in high-touch areas such as doorknobs, light switches and countertops, can help reduce the spread of the virus. In community settings, such as schools and nursing homes, increased vigilance in cleaning and maintaining hygiene can help limit outbreaks.