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.