Hydroalcoholic gel has become a widely used hygiene tool, often applied before eating, after touching public surfaces, or during daily errands. However, despite these precautions, gastroenteritis—commonly known as the stomach flu—continues to appear seasonally, and this year it is showing up earlier than usual. A Belgian virologist has pointed out that the effectiveness of hydroalcoholic gel against norovirus, the main cause of winter gastroenteritis, is limited. Norovirus is responsible for over 90% of seasonal outbreaks and is highly contagious, making it a significant public health concern. Johan Neyts, a virologist from KU Leuven, explains that norovirus is resistant to the alcohol found in hydroalcoholic gel. This resistance is worsened by the virus's extreme contagiousness—just 18 viral particles can cause an infection. This year, norovirus has been circulating earlier in Belgium, possibly due to an unusually dry autumn, which may have influenced the virus's spread. One key issue with hydroalcoholic gel is that it disinfects rather than cleans. While it can kill many microorganisms on the skin, it does not remove them. Norovirus has a unique structure that allows it to survive the alcohol in the gel. As a result, even after thorough hand rubbing, live viral particles may still remain on the hands, increasing the risk of transmission. The most effective way to combat norovirus is by washing hands with water and soap for at least 30 seconds. This mechanical action physically removes the virus from the skin and flushes it away with water. For surfaces, diluted bleach is more effective than alcohol-based sprays in eliminating norovirus. The real danger of gastroenteritis comes not from the symptoms like vomiting or diarrhea, but from the severe dehydration they can cause, especially in young children and the elderly. According to American health authorities, norovirus causes about 685 million cases and leads to an estimated 212,000 deaths worldwide each year. Preventing norovirus requires consistent hygiene practices, including careful handwashing with soap and water, thorough cleaning of surfaces, and quickly isolating those who are sick to limit its spread.