Significant decline in pneumonia admission rate after the introduction of routine 2+1 dose schedule heptavalent pneumococcal conjugate vaccine (PCV7) in children under 5 years of age in Kielce, Poland

This study was performed to estimate the effect of heptavalent pneumococcal conjugate vaccine (PCV7) on the pneumonia admission rate in children younger than 5 years of age, after the introduction of routine 2+1 dose schedule immunization. We compared the pneumonia admission rate (number of cases per 1,000 population) 2 years before and 2 years after the introduction of PCV7 in 2006. Only children with radiologically confirmed pneumonia were analyzed. The vaccination rate in the analyzed periods was around 99%. In the period preceding the implementation of PCV7, the average pneumonia admission rate was 41.48/1,000 and 6.15/1,000 for 1-year-old and 2-4-year-old children, respectively. Statistical analysis showed a significant fall in this rate in two consecutive years after PCV7 implementation (p < 0.0000001 for 1-year-old and p = 0.011 for 2-4-year-old children, respectively). In the first year of vaccination, the admission number decreased in these two groups by about 65 and 23%, respectively. In the second year, only a few percent fall in the admission rate was noted. In children younger than 2 years of age, the age group targeted for vaccination, pneumonia-related healthcare utilization declined substantially following PCV7 introduction. These results suggest that PCV7 may play an important role in reducing the burden of pneumonia in Poland.