It's not just your imagination; norovirus cases are indeed increasing, and this trend is expected to continue

By Lisa Marie Basile | Fact-checked by Davi Sherman
Published February 28, 2024

Key Takeaways

  • Norovirus rates are rising in the Northeastern and Western United States. However, experts say numbers can be hard to track accurately due to delays in reporting and a lack of formal diagnoses.

  • Norovirus is known to spread rapidly, especially through the cooler months.

  • The best way to stay safe is to practice excellent hygiene.

Cases of norovirus are rising in the Northeastern US, with just over 13% of tests returning positive results during the week of February 17, according to Centers for Disease Control and Prevention (CDC) data.[] 

Just behind the Northeast, the Western US is seeing the second-highest norovirus rates (12.1%) in the country. The Midwest is seeing 10.2% of tests coming back positive, while the Southern region is seeing the lowest rates at 9.5%.[][] 

The highly contagious norovirus is the leading cause of acute gastroenteritis globally, leading to vomiting, diarrhea, and dehydration.[][]

According to Toufic Kachaamy, MD, Chief of Medicine and Director of Gastroenterology and Endoscopy at City of Hope in Phoenix, AZ, “[Norovirus is] notorious for rapid and effortless transmissibility through contaminated food, surfaces, or direct person-to-person contact via the oral route.” The body, he explains, requires a very low dosage of the viral particles for infection to settle in. 

Every year, there are an estimated 19 to 21 million norovirus illnesses. While it can affect people of any age, it causes an estimated 900 deaths annually, mostly among people aged 65 and older. Most patients experience a short course of sickness—one to three days—with rapid resolution, David Cutler, MD, a family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA, adds.[]

“The problem is that norovirus is a whole group of viruses,” Dr. Cutler says. “There isn’t one particular virus.” While a patient might develop immunity against one type of norovirus, there are many strains, he explains. It’s unknown just how long protection can even last, and a patient’s genetic makeup can play a role in this. The CDC says that when a new strain of norovirus is unleashed, it’s possible to see a 50% jump in cases.[][] 

While cases may be increasing at a seemingly alarming rate (with media coverage detailing, for example, cruise ships full of sick passengers), the outbreaks are actually on par with seasonal trends.[][]

In the US, norovirus tends to occur more often during the cooler months, from November to April. The number of outbreaks reported during the 2023–2024 seasonal year is within the range reported during the same months from 2012–2020 and 2021–2023, the CDC says.[]

“Its prevalence intensifies during the winter months, a period characterized by the increased indoor congregation of individuals, particularly children, facilitating heightened exposure to potentially infected persons,” Dr. Kachaamy says.

In general, Dr. Cutler says, the virus is not just affecting the Northeast. “It’s ubiquitous and everywhere,” he says. “It’s not out of the ordinary. And while the CDC does track it, most cases don’t even get diagnosed as norovirus.” 

The CDC says that some US laboratories that report weekly norovirus cases to the CDC may experience reporting delays, leading to incomplete regional data.  

Don't miss work, stay safe

Dr. Cutler says it’s critically important not to undermine the power of good hygiene. You should also practice frequent handwashing and clean your food and food prep surfaces, as food is a main transmission culprit.[] 

Dr. Kachaamy adds that the virus is smart; it can be resilient against conventional antimicrobial agents like hand sanitizer. The best bet is to wash your hands with soap and water in addition to using hand sanitizer.[] 

To prevent the spread of the illness, the CDC also recommends disinfecting surfaces with chlorine bleach or another disinfectant after someone vomits or has diarrhea.[]

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