Impact of infant pneumococcal conjugate vaccination on community acquired pneumonia hospitalization in all ages in the Netherlands

Background The long-term impact of pneumococcal conjugate vaccines on pneumonia hospitalizations in all age-groups varies between countries. In the Netherlands, the 7-valent pneumococcal conjugate vaccine (PCV7) was implemented for newborns in 2006 and replaced by PCV10 in 2011. We assessed the impact of PCVs on community-acquired pneumonia (CAP) hospitalization rates in all age-groups. Methods A time series analysis using Poisson regression was performed on 155,994 CAP hospitalizations. Hospitalization rates were calculated using the total number of hospitalizations as denominator. The time trend in the pre-PCV period (1999–2006) was extrapolated to predict the hospitalization rate in the post-PCV period (2006–2014) if PCV had not been implemented. Rate ratios over time were calculated by comparing observed and predicted time trends. Results In children <5 years of age, the observed hospitalization rates during the post-PCV period were significantly lower than predicted if PCV had not been implemented (0–6 months: 0.62, 95% CI: 0.41–0.96; 6 months – 1 year: 0.67, 95% CI: 0.50–0.90; 2–4 years: 0.78, 95% CI: 0.61–0.97). In all other age-groups, rate ratios declined over time but did not reach statistical significance. Conclusions After introduction of PCV, CAP hospitalizations declined in young children but no clear impact of PCV on CAP hospitalizations was seen in other age-groups.