The antibody avengers and the norovirus vaccine

Scientists have identified powerful antibodies that offer broad protection against norovirus, paving the way for a new and effective norovirus vaccine.

Researchers from the University of Texas at Austin (TX, USA), in collaboration with the University of North Carolina at Chapel Hill (NC, USA) and the National Institutes of Health (MD, USA), have applied advanced molecular analysis to identify potent antibodies capable of neutralizing multiple norovirus strains. Their findings could lead to the development of an effective norovirus vaccine and new therapeutic treatments for norovirus-related gastroenteritis.

Norovirus is a highly contagious virus that affects approximately 700 million people annually. It is the most common cause of acute gastroenteritis globally, and the leading cause of foodborne illness in the US. While most individuals recover from infection, norovirus poses a severe risk to young children, the elderly, and those with weakened immune systems.

There is no specific treatment for norovirus, leaving a significant research gap for the development of new therapies. Developing a vaccine has been particularly challenging due to the lack of information on conserved neutralizing epitopes, as well as the virus’s ability to mutate rapidly and escape herd immunity. This could be about to change.

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The research team analyzed immune responses in the serum of individuals who had received an experimental oral adenoviral-vectored norovirus vaccine developed by Vaxvart (CA, USA). Using high-resolution liquid chromatography–tandem mass spectrometry (LC-MS/MS)–driven proteomics to detect circulating serum antibodies before and after immunization, they narrowed their study down to two participants. These individuals displayed a breadth of serum neutralization responses across norovirus GII.4 variants or GII genotypes.

Upon further analysis of the neutralizing antibodies produced by the two participants, they discovered that they could target multiple norovirus strains, including those responsible for 75% of global outbreaks. Among these, the antibody VX22, in complex with the protruding domain of norovirus VP1 – responsible for host receptor interaction and immune recognition – stood out for its ability to bind to a highly conserved epitope, making it a strong candidate for future vaccine development.

The discovery of these antibodies offers a potential path to a vaccine that provides long-lasting, broad protection. Additionally, these antibodies could serve as a post-infection treatment for immunocompromised individuals.

“Norovirus cases this winter have surged to twice the two previous annual peaks, which really underscores the fact that norovirus is both prevalent and rapidly evolving, and we need a vaccine against it to reduce the global burden of diseases associated with norovirus,” explained Juyeon Park, first author and Postdoctoral Researcher at UT Austin. “Our findings can better inform the future design of vaccine development against norovirus.”

The researchers are now refining vaccine designs and expanding their research to test effectiveness in vulnerable populations, moving closer to a long-awaited norovirus vaccine.