The study, published in the online medical journal PLoS Medicine, found the virus mutates genetically, similar to the virus that causes influenza, therefore, as with flu, a vaccine could be possible.

The University of North Carolina at Chapel Hill researchers analyzed the relationships among the gene sequences of the norovirus strains that have been isolated over the past 20 years.

"What we've found is that the GII.4 arm -- of the noroviruses -- keeps changing," one of the study's authors, Lisa Lindesmith, said in a statement. "Whenever we're seeing big outbreaks of norovirus, we're also seeing genetic changes in the virus."

Noroviruses are very contagious -- it may only take one or two viral particles to become infected, Lindesmith said.

"A vaccine may have an important role, too, especially among the elderly and other people particularly vulnerable to the effects of the illness," Lindesmith said.

In the meantime, good hand washing is critical to prevent the spread of the virus, Lindesmith advised.