Norovirus: A Silent but Deadly Threat

Norovirus is notorious for its contagiousness, infecting the mucosal tissues in our gut and leading to a whopping 20 million cases of acute gastroenteritis each year in the U.S. This formidable virus results in around 70,000 hospitalizations, 800 deaths, and rakes up $10.6 billion in healthcare costs annually. While most people recover after a few uncomfortable days, norovirus is particularly dangerous for older adults and those with weakened immune systems. Strikingly, no vaccine has been available to fend off this menacing virus—until now!

Exciting News: VXA-G1.1-NN Oral Vaccine Surges Ahead!

A recent Phase 1b trial of VXA-G1.1-NN, an innovative oral vaccine developed by Vaxart, is illuminating the path to potential immunity against norovirus. "Norovirus can be tough to battle since it can linger on surfaces for up to a month," warns Brian Labus, an epidemiologist at the University of Nevada, Las Vegas. Just 10 viral particles are enough to trigger an infection, with each infected individual capable of producing billions of them.

How Does This Novel Vaccine Work?

VXA-G1.1-NN utilizes a non-replicating adenovirus to express a norovirus capsid protein and is ingeniously designed as a small tablet. This allows it to bypass the stomach, releasing its contents in the small intestine, where it triggers an immune response. Previous studies demonstrated its efficacy in healthy adults aged 18 to 49, showing promising signs.

Trial Highlights: Testing the Waters with Older Adults

In this latest trial, 65 participants aged between 55 and 80 received two doses of the oral vaccine at various strengths, while a control group took placebo tablets. The results were encouraging—there were no serious adverse events reported, and most side effects were mild, primarily headaches and fatigue. Remarkably, adverse reactions decreased after the second dose.

Immunity and Hope: Vaccine Shows Robust Responses

The study unveiled robust immune responses, producing immunoglobulin G (IgG) and immunoglobulin A (IgA) antibodies that persisted for up to 210 days. First author Becca Flitter, Director of Immunology at Vaxart, expressed her exhilaration, stating that the vaccine performed just as well in older participants as it did in younger ones—an unexpected and thrilling outcome.

A New Hope for Norovirus Vaccination?

The vaccine's capacity to stimulate immunity at the mucosal level—where norovirus typically enters—is particularly groundbreaking. "Achieving such a response from an injected vaccine is challenging," Flitter elaborated. Labus added that this novel vaccine could potentially alter the game of norovirus prevention, with the hope that it could protect against multiple strains.

Looking Ahead: A Vaccine in Our Future?

If all goes as planned, Vaxart anticipates the oral vaccine will be available to the public within the next two to three years. This could mark a significant turning point in the fight against the relentless norovirus!