The Norovirus Surge Across the United States

The Centers for Disease Control and Prevention (CDC) reports a notable spread of the norovirus in the Northeast United States, with the three-week average positive tests hitting 13.9% recently, maintaining a positive rate above 10% since mid-December 2023. Besides the Northeast's surge in norovirus cases, other areas are also reporting increases in positive tests recently: the South at 9.5%, the Midwest around 10%, and the West at approximately 12%. ¹

“Norovirus is the leading cause of vomiting and diarrhea from acute gastroenteritis (inflammation of the stomach and intestines) among people of all ages in the United States,” according to the CDC. “In the United States, outbreaks of norovirus occur most frequently during late fall, winter, and early spring. There may be variation in the timing of outbreaks between regions and between communities in the same region.” ²

Healthcare facilities, particularly long-term care facilities and hospitals are the most common settings for norovirus outbreaks in the United States and other industrialized countries, with over half of all reported outbreaks occurring in long-term care facilities. Outbreaks can be introduced by infected patients, staff, visitors, or contaminated food and sometimes last months, often resulting in more severe or even deadly illnesses in these settings.³

From a collaborative meeting held between the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO), they issued a summary report declaring the 3 leading causes of foodborne illnesses were human norovirus, then hepatitis A and hepatitis E. ⁴

Norovirus is also the leading cause of food-related illness outbreaks in the U.S., responsible for about 50% of all cases, primarily in restaurants and catered events, often due to infected food workers touching ready-to-eat foods. Outbreaks can stem from food contaminated at the source, such as oysters or produce exposed to contaminated water.

Foodborne illness is a very frequent occurrence in the US. The CDC estimates that 1 in 6 Americans (or 48 million people) get sick, 128,000 are hospitalized, and 3,000 die from foodborne diseases annually in the US.⁴

Schools, childcare centers, and cruise ships are also frequent outbreak locations, with the latter known for high-profile outbreaks despite accounting for only 1% of all reported cases. The virus's spread is facilitated by close quarters, shared spaces, and high-touch surfaces in these environments, compounded by its persistence on surfaces and resistance to many disinfectants.³

Cunard Cruise Line’s Queen Victoria cruise ship is under investigation by the Center for Disease Control and Prevention (CDC). During the voyage, 129 out of 1,824 passengers (7.07%) and 25 out of 967 crew members (2.59%) reported illnesses, with diarrhea and vomiting being the predominant symptoms noted. The causative agent for the outbreak is still unknown.

Similarly, in January 2024, the CDC documented Celebrity Cruises' ship, Celebrity Constellation, had a norovirus outbreak. During the voyage, 92 out of 2,056 passengers onboard (4.47%) and 8 out of 948 crew members (0.84%) reported falling ill, with vomiting and diarrhea being the predominant symptoms experienced.⁵

The rise in norovirus cases across the US, especially in the Northeast, highlights the need for improved prevention and hygiene practices. Health authorities and individuals must work together to control the virus and public health.

References

1. Irwin, L. Norovirus Slams Northeat US Hardest in Recent Weeks. CDC. Published February 22, 2024. Accessed February 23, 2024. https://thehill.com/policy/healthcare/4484460-norovirus-slams-northeast-us-hardest-in-recent-weeks-cdc/
2. CDC. Norovirus Regional Trends. Published February 22, 2024. Accessed February 23, 2024. https://www.cdc.gov/surveillance/nrevss/norovirus/region.html#north
3. CDC. Common Settings of Norovirus Outbreaks. Published May 10, 2023. Accessed February 23, 2024. https://www.cdc.gov/norovirus/outbreaks/common-settings.html
4. Parkinson, J. Leading Causes of Viral Foodborne Illness: Norovirus, Hepatitis A, E. Contagion. Published October 24, 2023. Accessed February 23, 2024. https://www.contagionlive.com/view/leading-causes-of-viral-foodborne-illness-norovirus-hepatitis-a-e
5. Abene, S. Investigation Underway on Queen Victoria Cruise Ship Following Illness Outbreak. Contagion. Published February 15, 2024. Accessed February 23, 2024. https://www.contagionlive.com/view/investigation-underway-on-queen-victoria-cruise-ship-following-illness-outbreak