In recent weeks, cases of viral gastroenteritis caused by the virus have been spreading in the United Kingdom Kawasaki variant of Norovirus, a very common RNA intestinal virus that causes over 90% of gastroenteritis nonbacterial in humans. The infection causes nausea, vomiting, diarrhea, abdominal cramps and mild fever. In Britain this year the prevalent strain of Norovirus, causing around 70 percent of infections, is GII.17, commonly called Kawasaki because it was first identified in 2014 in Kawasaki, Japan. The number of cases has increased significantly in recent weeks and is higher than in previous years, an increase seen across all age groups and particularly among adults aged 65 and over. The news is that right in the UK a vaccine against Norovirus will be tested for the first time, built with technology
What is the Kawasaki Norovirus strain
Norovirus strains are very frequent and are recognized globally as the cause of more than 90% of gastroenteritis nonbacterial in humans. The GII.17 variant, commonly known as Kawasaki, has been one of the predominant variants in recent years: for about 10 years, in fact, the GII.17 Norovirus infection has been prevalent compared to other Norovirus variants in different parts of the world (Canada, China, Germany, Hungary, Italy, Japan, the Netherlands, New Zealand, Russia, Slovenia, South Korea, Thailand and the United States).
This variant 17 of the GII strain was isolated in the winter of 2014-2015 during an epidemic in China and Japan and was called GII.17 Kawasaki precisely from the name of the Japanese city.
It has a particular structure of capsidthe protein structure that coats the virus: compared to the GII.4 variant that was most widespread in the past, Kawasaki has the ability to alter the bond between the virus and the host cell in a different way, raising concerns about how the virus spreads.
In general these pathogens have high genetic variability, they are highly infectious therefore a few units are enough to cause an infection and they are very resistant and persistent in the environment (they can survive up to 60°C).
How this intestinal virus is transmitted
Norovirus epidemics occur more frequently in the winter period and are favored by the cold climate, which is why it is also known as “winter vomiting virus“. Transmission usually occurs for fecal-oral routein most cases through contaminated food or water because they have come into contact with feces of diseased organisms. In some cases the virus is transmitted via aerosol from person to person or per contact with contaminated surfaces.
Certain foods more than others, particularly raw shellfish or poorly washed fruit and vegetables, can be vehicles for transmitting the virus. Gastrointestinal forms of Norovirus can be transmitted more rapidly in contexts of communities in confined environments such as hospitals, retirement homes, schools or cruise ships.
What are the symptoms of Kawasaki and how are Noroviruses treated
The most common symptoms are those typical of gastroenteritis characterized by nausea, vomiting, diarrhea, abdominal cramps andslight feverish state; however, in most cases they are short-lived. The incubation period of the virus is 12-48 hours, the infection can generally last from 12 to 60 hours.
There is no specific treatment for Norovirus, but you can ease the symptoms by drinking fluids to compensate dehydration due to vomiting and diarrhea. The important news, however, is given by the fact that this year and in the United Kingdom a new vaccine against Noroviruses, with mRNA technology also used for the anti-Covid-19 vaccine.
As regards the preventionaccording to the indications of the Istituto Superiore di Sanità, the use of hygiene measures preventative measures in food preparation, such as washing hands well, washing fruit and vegetables and in the personal hygiene of those involved in handling and distributing food.
The situation in Italy and the UK
The new strain has been widespread in Italy since February 2015. At the moment, in Italy there are no official reports of increases in Norovirus infection compared to the usual values for the period.
The situation therefore mainly concerns the United Kingdom. Effectively, the UK Health Security Agency in the weeks between 14 and 27 October 2024 noted an increase in the number of infections earlier than in previous years and a number of outbreaks since the beginning of the 2024/2025 season 26% higher than the average of the last five years. Cases remained high across all age groups, but increased especially among adults aged 65 and older.
The causes of this increase in infections in the UK are not yet known, but one of the reasons is hypothesized general reduction in hygiene measures compared to the period of the Covid -19 pandemic which also reduced the contagion of other viruses and at the same time an improvement in detection and diagnosis systems which immediately highlighted new cases
