Pediatric invasive pneumococcal disease in Taiwan following a national catch-up program with the 13-valent pneumococcal conjugate vaccine

Background: Seven-valent pneumococcal conjugate vaccine (PCV) has been available in Taiwan since late 2005. A national catch-up program was launched in Taiwan in 2013, providing 1 dose of 13-valent PCV to children aged 2-5 years. Here, we report the epidemiology of invasive pneumococcal disease (IPD) in children aged ≤5 years in this setting. Methods: We collected demographic and clinical information for pediatric patients (≤5 years) with IPD between 2008 and 2013. The incidence of IPD was estimated. The logs for PCV import into Taiwan were obtained to evaluate the impact of PCV usage on IPD epidemiology. Results: The overall incidence of IPD in children aged ≤5 years was 15.9 cases per 100,000 person-years. The IPD incidence caused by 7-valent PCV serotypes decreased significantly from 10.0 cases per 100,000 person-years in 2008 to 2.3 cases per 100,000 person-years in 2013. The incidence of IPD caused by serotype 19A increased substantially from 1.7 cases per 100,000 person-years in 2008 to 10.3 cases per 100,000 person-years in 2012, followed by a significant decrease to 5.6 cases per 100,000 person-years in 2013. The significant decrease in the incidence of serotype 19A IPD occurred primarily in children aged 2-5 years. Conclusions: The 13-valent PCV catch-up program was associated with a significant decrease in serotype 19A IPD incidence in 2013, primarily in children eligible for the 13-valent PCV immunization. Continued surveillance is necessary to assess the further impact of the national catch-up program on pediatric IPD epidemiology in Taiwan.