Research shows unvaccinated adults account for severest cases of the flu

Researchers at Duke Medicine published study results on Feb. 10 that showed two patients treated for flu out of 22 who required intensive care had received a flu vaccination prior to getting sick.

Researchers studied the first 55 patients to be treated for flu at the academic medical center. Of those 55 patients, 48 were infected with the H1N1 virus.

"Our observations are important because they reinforce a growing body of evidence that the influenza vaccine provides protection from severe illness requiring hospitalizations," Cameron Wolfe, the study's lead author and an assistant professor of medicine at Duke, said. "The public health implications are important, because not only could a potentially deadly infection be avoided with a $30 shot, but costly hospitalizations could also be reduced."

Wolfe said that 22 of the patients treated at Duke University Hospital were tested for the flu using a rapid influenza test that showed negative for the flu, when patients tested positive by other means. As a result of the negative test, the patients were not prescribed antiviral medications that would have been effective if taken within the first 48 hours of showing symptoms.

"Together, our observations during this influenza season support a high prevalence of the H1N1 virus affecting young adults and requiring ICU care, high false negative rates of rapid flu tests, and delay in starting antiviral treatment," Wolfe said. "Added to the finding of very low vaccination rates among both hospitalized and ICU admissions, our observations support previous findings that vaccination reduces the severity of disease and vaccinations should be encouraged as recommended by the U.S. Centers for Disease Control and Prevention."

The study results were published online in the American Journal of Respiratory and Critical Care Medicine.