It's all about a unique mutation: researchers have discovered why some individuals do not fall ill from norovirus.

The norovirus, often referred to as the "winter vomiting virus," is a highly contagious and resilient pathogen that causes widespread gastrointestinal illnesses. It affects approximately 685 million people annually and is known for its rapid transmission in close-contact settings such as hospitals, nursing homes, schools, and cruise ships. However, there are individuals who, due to a unique trait, are immune to it, reports BBC.

The resilience of norovirus is a key challenge in combating its outbreaks, as it can withstand extreme conditions, including temperatures up to 70 degrees Celsius, freezing, and prolonged survival in dry environments. The virus's robust protein shell protects it from alcohol-based disinfectants and cleaning agents, rendering many standard cleaning protocols ineffective, as explained by Patricia Foster, a distinguished professor of biology at Indiana University Bloomington.

The virus's ability to infect humans with just ten particles, compared to 100-400 particles for SARS-CoV-2, illustrates its virulence well. However, some individuals possess innate biological traits that make them more resistant. Various studies have shown that about 20% of people of European descent have a mutation in the FUT2 gene, which disables the enzyme necessary for producing certain cell receptors required by norovirus to infect the body.

These individuals, known as non-secretors, are naturally protected from the GII-4 strain, which is responsible for most outbreaks worldwide. Blood type also plays a significant role: people with blood type B demonstrate greater resilience compared to those with types A, AB, or O, researchers state. Despite this, norovirus continues to evolve, finding alternative ways to infect even those with partial resistance.

Foster emphasizes that the virus is becoming increasingly adept at interacting with various cell binding sites, highlighting the urgent need for more effective interventions for its treatment and prevention. The impact of the virus on various aspects of our lives is substantial: it causes 200,000 deaths annually, primarily in low-income countries, and a significant number of hospitalizations in developed nations like the United States.

Efforts to develop a vaccine against norovirus face numerous challenges. Its rapid evolution and genetic variability necessitate that vaccines target multiple strains simultaneously. However, advancements in laboratory techniques, such as culturing norovirus in human intestinal cells, have opened up opportunities to study vaccine efficacy.

Researchers advocate for the use of polyvalent vaccines to provide broad protection, especially in young children, to prevent immune imprinting—a suboptimal immune response caused by mismatched recognition of viral strains. Companies like Moderna and HilleVax are already conducting clinical trials using mRNA technology and virus-like particles to stimulate immunity without infection. The potential success of these vaccines lies in their ability to adapt to new strains and provide lasting immunity.

Researchers maintain cautious optimism: some compare the situation to flu vaccines, which require regular updates, while others suggest more durable solutions similar to vaccines for respiratory syncytial virus. Achieving even partial success in vaccine development could significantly reduce the global threat to healthcare systems posed by norovirus.

This material is for informational purposes only and does not contain advice that may affect your health. If you are experiencing issues, please consult a professional.