Hospitalization for respiratory syncytial virus infection and invasive pneumococcal disease in Danish children aged <2 years: a population-based cohort study.

BACKGROUND Previous population-based studies have reported a temporal association between respiratory syncytial virus (RSV) infection and invasive pneumococcal disease (IPD). We examined this association at an individual level in the Danish population. METHODS Using registry information about hospitalization for RSV infection and IPD in Denmark, we conducted a prospective, population-based cohort study and examined the associations between hospitalization for RSV infection and IPD. RESULTS In our cohort, no persons aged > or =2 years experienced IPD within 30 days after hospitalization for RSV infection. Among children aged <2 years, children who were hospitalized for RSV infection had a significantly increased risk of IPD during the 30 days after hospitalization, compared with those who were not hospitalized for RSV infection (adjusted rate ratio, 7.1; 95% confidence interval, 3.6-14.3). Likewise, hospitalization for a non-RSV respiratory infection increased the risk of IPD during the 30 days after hospitalization (adjusted rate ratio, 4.5; 95% confidence interval, 2.0-10.0). IPD did not increase the risk of hospitalization for RSV infection among children aged <2 years. CONCLUSIONS Both recent hospitalization for RSV infection and recent hospitalization for non-RSV respiratory infection increased the risk of IPD among Danish children aged <2 years.