Norovirus, Kawasaki variant record spreading

Experts have reported an intense spread of the Norovirus in the Northern Hemisphere, with 91 outbreaks occurring in the US in the first week of December 2024 alone, and further outbreaks having been reported in the aftermath of the Los Angeles fires. An article published in Eurosurveillance last September highlighted a surge in cases in six European countries: the United Kingdom, Austria, France, Germany, Ireland, and the Netherlands. According to scientists, the cause of this increase in the circulation of Norovirus could depend on the greater spread of a more contagious variant, GII.17, known as ‘Kawasaki,’ from the Japanese city where it was first isolated in 2015. This assertion is corroborated by the United States Centres for Disease Control and Prevention (US CDC), which has reported that 70% of the 56 viruses isolated between September 1 and the end of 2024 belong to the GII.17 strain, a figure mirrored in the UK. According to Antonella Castagna, full professor of Infectious Diseases at the ‘Vita e Salute’ University and head of the Infectious Diseases Division at the San Raffaele Hospital in Milan, the basic immunity acquired from previous infections decreases over time, and the strains mutate rapidly, which is why Norovirus could be unknown to the immune system of many. At present, no vaccine for the Norovirus is available, although some trials are underway. Given the rapid mutation rate of virus strains, the development of a universal vaccine is challenging.