Intranasal Influenza Vaccine in a Working Population

In the present study, we assessed the incidence of adverse events and influenza-like symptoms in a working population in Switzerland that was vaccinated against influenza. A total of 12,582 individuals of working age (<65 years old) were offered a free influenza vaccine of their choice (injectable or intranasal vaccine) in October and November 2000. Of these individuals, 1600 were vaccinated against influenza. Ninety-seven percent of the vaccine recipients chose the intranasal vaccine, and 3% chose the injectable influenza vaccine. The incidence of influenza-like symptoms and side effects was 13% and 36%, respectively. Individuals who chose the intranasal vaccine were more likely to report side effects (OR, 3.23; 95% CI, 1.29-8.08). Facial paralysis was observed in 11 patients and was the most severe adverse event associated with the intranasal influenza vaccine. As a result of these adverse events, the intranasal vaccine was removed from the market in the fall of 2001.