A vaccine against norovirus is set to move into human testing. Norovirus causes 685 million worldwide outbreaks, kills 50,000 children every year in mostly developing countries, and is now prevalent in China.
Norovirus, commonly known as the “winter vomiting bug,” is the worldwide leader in causing gastrointestinal infections. Symptoms include abdominal pain, diarrhea, nausea, and then vomiting. Norovirus is considered extremely dangerous because it is highly contagious, mutates rapidly and there are no viral drugs that are effective to treat it. The illness can lead to severe dehydration, hospitalization and even death.
Transmission of norovirus tends to be through human handlers contaminating food by spreading tiny particles of vomit or feces from an infected person. Some recent studies warn that virus mutation may allow transmission through airborne particles released through sneezing or from dust. Such a development would multiply the annual numbers of infected individuals from the current one in every eleven people on the planet.
Clinical estimates of annual Chinese norovirus cases average about 6 percent of the population, but it hits about 16 percent for children less than 5 years of age. Reported epidemics of 20 or more persons in China have grown dramatically since 2014. About 93 percent of major outbreaks are related to school settings; with 39 percent in primary schools, 22 percent in childcare facilities, and 20 percent in secondary schools.
Chinese authorities have tried to downplay the risks of norovirus despite at least 616 provincial norovirus epidemic warnings over the last five years. But Chinese media over the last twelve months reported on high-profile norovirus scandals including food safety risks at an elite international school in Shanghai last October; 170 infected kindergarten students inundating Beijing emergency rooms in January; 150 sick tourists at Club Med Yabuli ski resort in Heilongjiang Province during Chinese New Year; and over 200 households suffering from diarrhea and vomiting in Beijing’s Chaoyang district in July.
The estimated annual global financial cost of norovirus is $60 billion. That is about $15 billion more than all insurance payouts for Hurricane Katrina; $40 billion more than the estimated costs of the Sept. 11 terrorist attacks, and $20 billion more than the 2011 Christchurch, New Zealand earthquake. U.S. customer fear over several norovirus food poisoning outbreaks almost bankrupted the Chipotle Resturant chain.
But San Francisco biotech start-up Vaxart just finished its initial “1b Phase” trial for the U.S. Food and Drug Administration (FDA). Eighty healthy volunteers who took its oral vaccines for multiple strains of norovirus developed antibodies in 86 to 90 percent of cases. Immunologists called the results as passing the FDA trial with “flying colors.”
It is expected that the FDA will review the Vaxart data and soon grant approval for a “Phase II” trial that will give the vaccine to a targeted population groups totaling several hundred individuals that have a high probability of being exposed to norovirus.
Given that there is no vaccine for norovirus, any level of positive immunology results for Phase II efficacy would likely justify FDA approval of conducting a Phase III long-term safety study to assess the risk/benefit relationship of the drug and to provide adequate data for the product package insert. Phase III trials typically require a large number of patients, often thousands, to measure the statistical validity of the results because patient age, sex, race, and other factors could affect the results.
If Vaxart’s Phase II and Phase III studies pass the rigorous FDA standards, the vaccine could be distributed under a Phase IV new drug application (NDA); while continuing to test the vaccine for side effects, marketing claims, and new formulations.
Chriss Street is an expert in macroeconomics, technology, and national security. He has served as CEO of several companies and is an active writer with more than 1,500 publications. He also regularly provides strategy lectures to graduate students at top Southern California universities.