Safety and effectiveness against respiratory tract infections for pneumococcal conjugate vaccine co-administered with routine vaccine combinations

Streptococcus pneumoniae is a major cause of bacterial pneumonia and other respiratory tract infections (RTI) in children. The heptavalent conjugated pneumococcal vaccine (PCV7) is offering a promising strategy against pneumococcal disease in children younger than 2 years. In this prospective epidemiological study in Germany, children between 2 and 6 months of age received in a 3:1 ratio a routine childhood vaccine combination with or without PCV7 according to a four-dose schedule. Five thousand nine hundred and eighty-four children were evaluable 1 year after the booster dose. Due to German guidelines children with underlying medical conditions were preferentially included into the PCV7 group and hence 66% of the children in the PCV7 group had at least one medical risk factor and 40% were preterm born compared to 18% and 6% in the control group. Overall PCV7 reduced respiratory tract infections by 10.5% (95% CI: 2.9-17.3%) and clinically diagnosed pneumonia by 6.3% (95% CI: -15.9 to 23.7%) in this unbalanced situation. In a propensity score matched pair analysis controlling for risk factors, effectiveness of PCV7 against pneumonia was 24.8% (95% CI: 0.9-43.1%). In children with at least one medical risk factor vaccine effectiveness against pneumonia was 38.4% (95% CI: 10.7-55.9%) compared to 10.9% (95% CI: -20.2 to 33.9%) without a risk factor. In preterm and term born children, PCV7 was well tolerated when simultaneously administered with widely used hexavalent routine vaccine combinations. The results demonstrate that PCV7 is safe and effective against RTI in preterm children and in children with comorbidities stressing the benefit of pneumococcal conjugate vaccine in these children at high risk for pneumococcal disease.