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The Tufts Daily
Where you read it first | Sunday, March 16, 2025

The ‘quad-demic’ is in town: RSV, COVID-19, influenza and norovirus

Low vaccination rates and a new strain of norovirus are wreaking havoc this flu season.

Quad-Demic Graphic

Graphic by Jaylin Cho

There’s a new term to describe the rise of respiratory illnesses this season: “quad-demic.” The “quad” in quad-demic refers to four diseases that are part of the outbreak: respiratory syncytial virus, COVID-19, influenza and norovirus. The suffix “-demic,” stemming from the word “epidemic,” signifies a large occurrence of a disease or illness in a community or specified area. Knowing pertinent information, keeping up with available data and learning how to prevent these illnesses are three key steps in managing and ending this quad-demic.

RSV is a common virus that causes symptoms associated with colds, including sore throat, runny nose and cough. It spreads through contaminated surfaces, respiratory droplets in the air and direct contact with infected individuals. It is quite contagious, especially given the low RSV vaccination rates across the United States. Fortunately, RSV infection rates seem to be declining, according to a report put out by the Centers for Disease Control and Prevention on Friday.

COVID-19 and influenza also show low vaccination rates this year. Both respiratory illnesses spread through respiratory droplets in the air and direct contact with infected individuals.

The final piece of the quad-demic, norovirus, often called the “stomach bug” or “stomach flu,” is a winter virus that commonly causes symptoms including vomiting, diarrhea and stomach pain. It is extremely contagious — spread through contaminated food, water, surfaces and infected individuals — and its symptoms are most often seen 12–48 hours after exposure. Furthermore, research has proven that infected individuals are able to spread norovirus for two weeks or more after symptoms subside.

The highly contagious nature of norovirus has led to a large number of outbreaks, contributing to the quad-demic. According to the CDC’s NoroSTAT database, from Aug. 1, 2024 to Jan. 15, there were 1,078 norovirus outbreaks across the United States in the 14 participating states, Massachusetts included. This is a huge jump from the 557 outbreaks reported during the same period last year. What’s more, just from Jan. 2–9, 97 norovirus outbreaks were reported by the 14 states.

So, what is driving this concerning surge in norovirus cases? According to experts, this increase in cases is explained by a new strain of norovirus called the GII.17[P17]. In the past decade, the majority of norovirus outbreaks in the United States were traced to the strain GII.4; however this year only 7% of cases have been linked to GII.4. More data and research on this strain will be required to fully understand what in this strain is causing increased rates of infection.

Looking at Massachusetts data on these viruses is crucial in order to understand how this quad-demic could impact the Tufts community. The CDC puts out weekly updates and a report in their Respiratory Illnesses Data Channel on Fridays, which presents data both from state and national levels. This includes data on three of the four respiratory illnesses in the quad-demic: RSV, influenza and COVID-19. 

The CDC’s dashboard currently classifies the overall respiratory illness activity in the state of Massachusetts as “high” out of the predetermined levels of minimal, low, moderate, high and very high.

With such high infection levels, are emergency departments getting overwhelmed? Looking at emergency department visit data, COVID-19 and RSV emergency department visits are classified as “low” and decreasing. However, influenza emergency room visits have been classified as “very high” by the CDC and are on the rise.

Furthermore, wastewater viral activity levels have been crucial in showing levels of infections and risk of developing infections. In Massachusetts, influenza wastewater viral activity levels have been classified as “very high” and COVID-19 activity levels as “high,” while RSV is now classified as “moderate.”

Apart from knowing the data, prevention is key in managing the spread of illnesses, including those in the quad-demic. Touching contaminated door handles, dining halls serving spoons and bathroom surfaces have all been linked to the spread of disease and infection. A great piece of advice is to keep up with hand hygiene, such as using hand sanitizer, which has been shown to be helpful in eliminating microbes from hands and helping prevent the spread of disease.

It is worth noting that though hand sanitizer helps prevent RSV and COVID-19, along with other illnesses, it is not effective against norovirus, which makes the management and prevention of the illness quite difficult. While still less effective than hand washing, hand sanitizer can be a good secondary option. With that being said, hand washing is one of the most effective ways of stopping the spread of infection and building healthier communities.

General health measures like maintaining a balanced diet, exercising and getting adequate sleep are all crucial in preventing and managing respiratory illnesses. If you are experiencing symptoms of a quad-demic illness, it would be beneficial to take a trip to Tufts University Health Services as soon as possible.


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