A fourth illness is making waves this virus season alongside the flu, respiratory syncytial virus and COVID-19, creating a quadruple threat for the U.S.
The norovirus (commonly known as stomach flu) is surging with levels not seen in more than a decade. Public health officials are warning that we might soon have a "quad-demic" on our hands.
According to the CDC, there were 495 norovirus outbreaks reported from last August to December and in the same period in 2023, there were 363 norovirus outbreaks reported. All data seems to point to an unusually high level of transmission of the norovirus expected for the rest of winter.
Norovirus causes acute gastroenteritis, an inflammation of the stomach or intestines. Most people get better within one to three days but they can still spread the virus for a few days after. The virus was discovered in 1972 when researchers were investigating an outbreak of gastroenteritis at an elementary school in Norwalk, Ohio, according to a study published in Viruses.
Five key points about the norovirus.
- Norovirus is the leading cause of vomiting and diarrhea, and foodborne illness in the U.S. Symptoms include body aches, diarrhea, fever, headache, nausea, stomach pain and vomiting.
- People of all ages can get infected and sick with norovirus.
- Proper handwashing and other simple steps can help prevent getting and spreading norovirus.
- There are no medications to treat norovirus and experts say it is critical to stay hydrated.
- The illness causes an average of 900 deaths annually, mostly among older adults, along with 109,000 hospitalizations and 19 million to 21 million cases in the U.S. each year.
Current prevalence of norovirus
At present, state and local health departments are not required to report individual noroviruses cases to the CDC. Of the voluntarily reported data on current outbreaks, California has the most number of cases (43), followed by Florida (24), New York (21) and Virginia (20), according to the CDC's CalciNet Data database.
Other states with high figures included Ohio, Wisconsin and Minnesota (18 each), Rhode Island (16), Oregon (13), West Virginia and Michigan (11 each).
What is contributing to high transmission?
Medical experts think that people have stopped practicing good hand hygiene with the threat of the pandemic behind us. And with this virus, experts say soap and water — not hand sanitizer — must be used to kill this highly infectious virus. According to LiveScience, the virus spreads easily through direct contact with an infected person or with contaminated surfaces, even after the infected person's symptoms have passed.
For the other three viruses (all respiratory) making up the quadruple threat, the CDC says the transmission levels are high and climbing, especially in southern, southwestern and western regions. Here are the CDC's recent observations:
- As of Jan. 3, the amount of acute respiratory illness causing people to seek healthcare is at a high level and continues to increase nationally.
- COVID-19 activity is increasing in most areas of the country.
- Seasonal flu activity continues to increase and is elevated across most of the country.
- RSV activity is very high in many areas of the country, particularly in young children.
What is the quad-demic's potential effect on hospitals?
Public health officials have warned about the possibility of a quad-demic, with all four of these prevalent viruses surging at the same time, according to Fortune. Some hospitals are limiting visitors or reinstating mask policies as a result. Hospitalizations are up sharply in major cities, including Los Angeles, New York and Chicago. This perfect storm of viruses comes as vaccination rates are down for flu, COVID-19 and RSV. There is no vaccine yet for norovirus.
"All of the viruses are here, it's just they're affecting different areas a little bit differently," Robert Hopkins Jr., MD, medical director of the National Foundation for Infectious Diseases, told Fortune. "I don't want to panic people, but I would say if you haven' been vaccinated and you’re eligible for vaccination — that means everybody 6 months of age and older—get that COVID shot, get that flu shot."”