New Norovirus Variant GII.17 Triggers Sharp Rise in Infections Across the US and Europe

Health authorities in the United States and Europe are raising alarms as a new norovirus variant, GII.17, drives a rapid increase in infection cases. Experts warn that the current norovirus season could be particularly severe, mainly because most people have little immunity against this newly dominant strain.

The rise in cases has been observed over the past few months, with infection numbers climbing faster than usual. Countries across Europe, along with the US, are reporting unusually high activity, especially in crowded and shared environments such as schools, daycare centers, hospitals, and nursing homes, where the virus spreads extremely easily.

Why the GII.17 Variant Is a Serious Concern

Norovirus is already known as one of the most contagious causes of stomach infections worldwide. The GII.17 variant, however, appears to spread even more efficiently than earlier strains.

According to infectious disease experts, including Ben Lopman from Emory University, norovirus activity is higher than expected for this time of year. Traditionally, norovirus infections peak around January, but the early surge suggests that this season may place a heavier burden on healthcare systems.

One major reason for this surge is low population immunity. When a new variant emerges, previous exposure to older strains may not provide adequate protection, leaving many people vulnerable to infection.

Symptoms Can Be Severe, Especially for High-Risk Groups

People infected with norovirus GII.17 commonly experience:

• Sudden and intense vomiting

• Watery diarrhea

• Stomach cramps

• Nausea

• Fever and body aches

• Extreme weakness and dehydration

While most healthy adults recover within a few days, the illness can be dangerous for young children, older adults, and people with weakened immune systems, who are at higher risk of severe dehydration.

Rising Case Numbers May Be Underestimated

In Germany, the Robert Koch Institute (RKI) reported more than 5,300 confirmed norovirus cases by mid-November 2025, marking a clear increase compared to the previous year. Health experts believe the real number of infections is likely much higher, as many people with mild symptoms do not seek medical care or testing.

Similar trends are being seen in other parts of Europe and the United States, indicating that GII.17 is spreading widely and efficiently.

A Virus That Is Hard to Control

One of the most challenging aspects of norovirus is its exceptional resistance. The virus can survive:

• Very high and very low temperatures

• Extended periods on surfaces

• Common cleaning agents

This durability allows norovirus to persist in the environment, making outbreaks difficult to stop once they begin.

Adding to the challenge, there is currently no vaccine and no specific antiviral treatment for norovirus infections. Care is mainly supportive, focusing on hydration and symptom management.

How Norovirus Spreads

Norovirus GII.17 spreads through multiple routes:

• Direct person-to-person contact

• Touching contaminated surfaces and then touching the mouth

• Consuming contaminated food or water

Because only a tiny amount of virus is needed to cause infection, outbreaks can spread rapidly in shared living spaces.

Prevention is the Best Defense

With limited medical options available, prevention is critical. Health experts strongly recommend:

• Washing hands thoroughly with soap and water

• Disinfecting commonly touched surfaces using appropriate disinfectants

• Avoiding food preparation when sick

• Keeping infected individuals isolated for at least 48 hours after symptoms stop

Good hygiene remains one of the most effective ways to slow the spread.

More:

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