Evaluation of the Effectiveness of Haemophilus influenzae Type b Conjugate Vaccine Introduction against Radiologically-Confirmed Hospitalized Pneumonia in Young Children in Ukraine

ObjectiveHaemophilus influenzae type b (Hib) conjugate vaccine was included into the national vaccination schedule of Ukraine in 2006. The objective of this study was to demonstrate the effectiveness of Hib conjugate vaccine against radiologically-confirmed hospitalized pneumonia in children.Study designChildren <2 years old with radiologically confirmed pneumonia admitted to 11 participating hospitals in Kiev and Dnepropetrovsk between April 2007 and June 2009 were included in a case-control evaluation. Four controls were matched to each case by date of birth (within 14 days) and outpatient clinic. We estimated ORs for vaccination and vaccine effectiveness ((1 − OR)*100%) using conditional logistic regression, adjusting for comorbid conditions and contraindications for vaccination.ResultsWe enrolled 188 case-children and 735 controls. Median age was 16 months (range 4-24 months). Fifty-one percent of cases and 67% of controls received ≥1 doses of Hib conjugate vaccine; 26% of cases and 37% of controls received ≥3 doses. The effectiveness of ≥1 dose Hib conjugate vaccine was estimated at 45% (95% CI 18%-63%).ConclusionsOur study showed that Hib infections are important causes of hospitalized radiologically confirmed pneumonia in young children in Ukraine.