Noroviruses are reminiscent of a series of nightmarish gastrointestinal symptoms, and the hated infections have been ramped this winter. So-called gastric influenza – Unrelated to the flu, but suddenly there is a strike and curses the victim with diarrhea and vomiting for 1-3 days.
However, unlike other common infectious diseases such as seasonal influenza and Covid, people avoid the norovirus, a notoriously infectious and resilient virus that is difficult to kill with common alcohol-based disinfectants. There is no vaccine to avoid being administered. Vaccine developers have been working for a long time to create vaccines. Currently, seven different candidates are at different stages of the clinical trial. However, while no one has proven to be effective enough to obtain approval in the US, there are several scientific barriers, but researchers quickly say that one approach addresses the challenge, They hope to provide effective tools for those who want to boost their immune system against troublesome infections.
What is norovirus?
Supporting science journalism
If you enjoy this article, consider supporting award-winning journalism. Subscribe. Purchase a subscription helps ensure a future of impactful stories about discoveries and ideas that will shape our world today.
Noroviruses are responsible for more than half of the US foodborne diseases, and the virus survives on the surface for up to two weeks, thrives in the face of common hand sanitizers, tearing the environments of cruise ships and cafeterias. Masu. Typical symptoms of an infection include diarrhea, vomiting, nausea and stomach pain. People can also experience fever, headaches and body pain. Severe vomiting and diarrhea cases increase the risk of severe dehydration.
Centers for Disease Control and Prevention Data on Norovirus outbreaks are very limited. The agency’s surveillance network for infections only includes 14 states. Still, these statistical painting paintings are tough. Reporting states have seen 1,078 suspected or confirmed outbreaks of norovirus from August 1, 2024 to January 15, 2025. When the reporting network is established.
Young children and people over the age of 65 are particularly vulnerable to severe illnesses. Every year, the virus causes over 2 million outpatient clinic visits, primarily young children, killing around 900 people in a year, mainly 65 years old and over. The infection is highly contagious and frequently causes large outbreaks, attacking these vulnerable groups vigorously, but for most people, symptoms last only a few days. Ming Tan, a scientific researcher at Cincinnati Children’s Hospital Medical Center, says fluctuations in the severity of the disease can be tricky when it comes to vaccine manufacturers.
“Some people don’t see it as a very important illness, and they say it’s terrible because it can make many people sick in certain close-up environments,” says Tan.
Challenges for vaccine manufacturers
The virus boasts several properties that are challenging targets for vaccine developers. First, like influenza, “noroviruses” are actually a group of viruses made up of around 48 so-called genotypes divided into 10 larger classes. Like influenza, the immune system trained to recognize one type of norovirus cannot necessarily protect against others. And the dominant strains frequently travel back and forth every two to four years, making it difficult for the immune system to maintain. (This year and last year were primarily caused by a strain called GII.17, but the previous season was led by a tension called Sydney.)
“There are many norovirus genotypes that can cause human disease, and each of these genotypes has a slightly different protein shell that I think requires a slightly different immune response.” The development of norovirus vaccines has led to the development of Moderna is a biotech company led by the company.
Another challenge is that noroviruses cause what scientists call mucosa, or mucosa, infection. In this case, it is a local infection of the intestinal surface tissue. (Influenza is a local mucosal infection in respiratory tissue.)
These local viruses are difficult for the body to remember and fight compared to systemic infections such as measles and chicken po, which affect the whole body and cause a normally robust and long-lasting immune response. “Muboclastic immunity is short-lived and not like systemic immunity,” says Lijuan Yuan, a viral immunologist at Virginia Tech. She points out that injected vaccines cause systemic immune responses rather than mucosa, which means there is less access to the virus. This cleavage makes the vaccine injected into a mucosal infection more likely to protect against severe illness, rather than completely preventing it.
Noroviruses are difficult to work in the lab. Preliminary vaccine experiments usually require animal models, but researchers do not have a good model of norovirus. This is because noroviruses in humans do not easily infect animals, so animal-specific noroviruses cause very different symptoms. Noroviruses also cannot grow well in cells, the original pointed out.
In the pipeline
Despite many obstacles, scientists are working on clinical trials to test half a dozen different vaccine candidates. All target primary surface proteins, or capsid proteins, that envelop norovirus molecules, but each uses several different approaches with their own strengths and weaknesses.
In one approach, scientists produce many of these so-called capsid proteins. Proteins spontaneously form empty structures that are the same shape as viruses. When these empty shells, called virus-like particles, are injected into a person, the body responds in the same way as it is the real thing, training the immune system. But creating virus-like particles takes time, Tan says. And while the vaccines have provided appropriate results in adult trials, they have little protection for children.
The second approach confers the ability to recruit common, usually mild respiratory viruses called adenoviruses, unable to replicate, and produce target norovirus proteins. Adenoviruses are packaged in oral vaccines, which are much easier to administer than injections, allowing direct training of the mucosal immune system. However, protection rates remain fairly low, Tan says.
The third approach uses the same mRNA technology that was used to create a portion of the covid vaccine. Genetic information for noroviral proteins is injected into vaccine recipients to trigger an immune response. This method is easier to implement and can be updated more easily as different strains of norovirus become dominant, says Fink. His team at Moderna has designed an mRNA norovirus vaccine, and the company is currently recruiting people to test how well it is. This allows scientists to compare MRNA technology that has disappointed researchers to date with virus-like particle and adenovirus approaches. “We still need to wait whether it has better effectiveness or not. [and see]Tan, who is not involved with any of these candidates, says.
Whichever vaccine does it through trials, you may not be able to gain annual ritual status for shots of flu first. Given that norovirus infections tend to get much worse for these groups, Fink says it is likely that they will be first offered to people over the age of 65 and immunocompromised. It will most likely be provided as an annual dose during the peak period of norovirus between November and April in the Northern Hemisphere. He points out that perhaps people planning on embarking on a cruise, or those who are hoping to be exposed to the virus otherwise could choose their dose as well. However, Tan is not convinced that healthy adults are very interested in the norovirus vaccine.
Fink says it’s still worth having a vaccine as a preventive option, even if it doesn’t fully protect it. “Even if you take norovirus, if you can change the burden of the disease so that it’s very mild, I think it’s a great success,” he says.
