Near disappearance of childhood invasive Haemophilus influenzae type b disease in Singapore

Abstract Background Haemophilus influenzae type b (Hib) conjugate vaccines have significantly limited Hib's disease impact in every country where it was introduced. We previously estimated invasive Hib disease incidence in Singapore at ∼4.4 per 100,000 children Methodology We retrospectively reviewed all invasive Hib cases from January 2004 to December 2012 (period 2) and estimated population-based incidence rates. Vaccine coverage was estimated from vaccine sales for 1994–2003, and from National Immunisation Registry for 2004–2010. Results There were 8 cases of invasive Hib disease in period 2, of whom 5 were 80%, with >99% of children receiving combination Hib-containing vaccines. Conclusions Childhood invasive Hib disease has nearly disappeared from Singapore, despite the absence of universal mass vaccination. We believe this is likely due to excellent uptake of combination vaccines.