Messenger RNA vaccines have been in the collective imagination since 2020, since they were the ones used to combat and end the coronavirus crisis. Even so, they had already been studied for decades. This has led to it being currently investigated as a method to fight other diseases such as HIV or even cancer. Now, the pharmaceutical company Moderna and the British National Health System (NHS) are testing the effectiveness of this tool for prevent infections caused by norovirus.
These pathologies are also known as ‘stomach viruses’ and mainly cause diarrhea. They may also be accompanied by fever, nausea, vomiting, abdominal pain or cramps and a feeling of general malaise, among others, describes the Mayo Clinic on its website. It affects about 685 million people and causes around 200,000 deaths worldwide annually. In addition, they tend to be transmitted in closed places where many people gather, such as schools, nursery schools, hospitals, cruise ships or nursing homes.
Isabel Jimeno, responsible for vaccines at the Spanish Society of General and Family Physicians (SEMG), warns that these infections They are highly transmissible. That is why it is important that the effectiveness of a vaccine like this be studied. “Any preventive measure is always good news.” The doctor explains that noroviruses are the cause of approximately half of gastroenteritis outbreaks, “especially those in winter.”
Penn Medicine
Typically, symptoms last between one and three days, but in severe cases the patient may require hospitalization. Adults over 60 years of age, people with other pathologies and children are the most vulnerable population and those at greatest risk of complications. “The smaller, the worse,” says Jimeno, referring to the last group.
If the test goes well, this would be the world’s first mRNA vaccine to combat norovirus infections. Currently, they do not have a specific treatment either, clarifies the SEMG doctor. Jimeno indicates that medications can only be prescribed to reduce fever and control malnutrition and dehydration through diet and replenishing electrolytes.
The clinical trial, called Nova 301, is scheduled to last two years. It will have 25,000 adults from various countries such as Japan, Canada and Australia. The NHS will participate in it with 27 primary and secondary care centers in England, Scotland and Wales, and will recruit around 2,500 citizens. The research will be done in a randomized manner, so half of the individuals will receive the vaccine and the other half will receive an injection of saline solution that will act as a placebo.
To track participants, they will need to use an electronic diary application on their smartphone to report on side effects or symptoms of acute gastroenteritis. Volunteers will have to provide this data daily for a week from the first injection and at least once a week after that.
How it works
Vaccines of this type use the genome of the virus against which the patient is to be protected. When injected, mRNA is introduced into human cells and the latter use it to produce proteins associated with the pathogen. Afterwards, the manufactured molecules activate the immune system to prevent the development of the disease if the person is exposed to it.
In the case of the product that Moderna wants to create, the mRNA contains instructions for creating a protein layer of three distinct noroviruses. The objective is for harmless particles similar to these pathogens to form that promote the production of antibodies when the time comes.
What to expect from the vaccine
To consider the trial results as meaningful, the vaccine would have to show an efficiency of at least 65% Patrick Moore declared to The Guardian. The doctor is the chief investigator of the trial in the United Kingdom. In previous phases of the trial they have been able to observe that the product has a good immune response in humans. Now we need to check if it is really effective against the virus and, if so, how long its effectiveness lasts.
If the project goes well, the company hopes to apply to regulators for commercialization in 2026. Once that is done, the review process can take up to a year, so at best would not see the light until 2027. More trials will also be carried out on adolescents and younger children, the British media reported.
Jimeno, of the SEMGbelieves that it could be a good advance, but also warns of the length of time these projects usually take to materialize. Furthermore, he adds, “it is one thing for it to be approved and another for it to reach the vaccination schedule.” To do this, the health system of each country must count the burden of the disease and make a comparison between the cost and the effectiveness it may have for the population. “Assuming everything went well, we would still have to wait a long time.”
