Scientists are less than five years away from producing a vaccine that could put an end to virulent norovirus outbreaks that plague hospitals, long-term care facilities and cruise ships.
“We are going to have a vaccine,” researcher Charles Arntzen said at the American Association for the Advancement of Science conference in Vancouver on Friday.
Yet he cautioned it would take more tweaking and clinical testing.
“The current vaccine as formulated is not ready for prime time,” said Arntzen, of the Arizona State University Centre for Infectious Diseases and Vaccinology. “If things go well, four to five years.”
A norovirus vaccine could save 20 million Americans each year from suffering the extreme vomiting and diarrhea caused by the virus. It could save money too: Norovirus costs the U.S. health care system $2 billion a year.
Arntzen’s team at BioVaxx Inc. are working on culturing a norovirus-like molecule in tobacco plants to create a powder vaccine, which is then combined with aloe plant-derived extracts and delivered as a dry nasal spray.
Another U.S. group, LigoCyte Pharmaceuticals, is also working on a vaccine, a version cultured in insects and delivered by a wet nasal spray. Results from a small clinical trial were published in 2011 and proved the vaccine worked.
Now, Arntzen said, the challenge will be getting regulatory approval and clinical testing.
Norovirus is the single most infectious virus on earth, according to the scientists, requiring only 18 particles of the billions shed by an infected person to be transmitted to a new host.
It causes an estimated 90 per cent of non-bacterial gastroenteritis outbreaks globally. It is resistant to disinfectants like alcohol wipes and hand sanitizers, though it can be inactivated using chlorine bleach. About 800 Americans die from the virus each year, mostly children and seniors.
“The hardest hit are the long-term care facilities,” said Jan Vinje, a specialist at the U.S. Centres for Disease Control and Prevention.
Vinje’s data showed 59 per cent of cases were in long-term care facilities, while restaurants accounted for eight per cent of cases, cruise ships, hospitals and schools four per cent each, and the remainder from various locales.
“This virus is very democratic,” Vinje said, “It affects everyone.”