Vaccine efficacy against Haemophilus influenzae type b in under-5 children; systematic review and meta-analysis

Background: Invasive Haemophilus Influenzae type b (Hib) disease is a major problem of the public health in the countries have not implemented Hib vaccine in their routine immunization. The aim this study was to summarize the best available evidences regarding vaccine efficacy of Hib in the children younger than 5 years of age. Methods: The study was a systematic review and meta-analysis of randomized controlled trials and quasi-experimental studies on children of general population with at-least two years of follow-up. We searched Medline, OVID, ISI, Cochrane (Central Register of controlled trials), Proquest, scopus, DARE, HTA, and NHSEED from first available time to the end of 2008. Types of acceptable interventions were conjugate Hib vaccines (PRP-T, HB-OC, PRP-OMP, PRP-D) compared with placebo, no treatment or not-relevant vaccines. The summary estimated effect was calculated with Random Effect model. The publication bias was assessed by Egger's and Begg's tests. Findings: We find nine article that met inclusion criteria. The pooled estimate for vaccine efficacy was 84 (95CI: 69-92) against invasive Hib diseases. The tolerability of vaccine was acceptable in all studies and the incidence rates of side effects were rare. Conclusion: The study shows that conjugated Hib vaccine could prevent about 84 percent of Hib aggressive diseases. In the case of approval in an economic evaluation, it is reasonable to implement such vaccine in the routine immunization system of Iran