Norovirus is a virus which can cause severe gastrointestinal illness (nausea, vomiting, and diarrhea). The illness usually lasts between 24 and 72 hours and can lead to dehydration in children, debilitated persons, and the elderly. This virus has been isolated as the cause of widespread illness on cruise ships. A recent study published in the December 8, 2011 edition of the New England Journal of Medicine reports promising results for a vaccine to prevent norovirus illness.
The study, sponsored by the National Institutes of Health and LigoCyte Pharmaceuticals, tested a vaccine on a group of healthy adults ranging in ages from 18 to 50. Some of the participants received two doses of the vaccine by nasal route while others received placebo. Participants were then inoculated with a common type of norovirus, called Norwalk virus. Those who received the vaccine had a lower rate of viral illness (37%) compared to the placebo group (69%).
This study, while showing encouraging results, highlights common limitations in clinical trials involving humans. The test subjects were healthy persons between 18 and 50 years old; however, those persons at greatest risk for complications from norovirus infection are not healthy persons between 18 and 50 years old-they are persons under 18, over 50, and those who are not healthy. It remains to be seen how effective the vaccine is (and what side effects occur) when tested on persons most at risk of complications from norovirus illness.