Haemophilus influenzae type b vaccine impact in resource-poor settings in Asia and Africa.

The Haemophilus influenzae type b (Hib) conjugate vaccine has been administered for almost 20 years in developed countries with remarkable success. More recently, the vaccine has been introduced in resource-poor settings, mainly those in Africa. African countries have documented large declines in Hib-invasive disease following universal vaccine introduction based on evaluation of routine surveillance data. As of 2007, only Mongolia in Asia had introduced the vaccine. Consequently, studies are limited to clinical trials in Bangladesh and Indonesia, and these also demonstrate substantial vaccine impact. Beyond invasive disease, three pivotal trials in Africa and Asia have demonstrated vaccine impact against clinical pneumonia end points. In all settings evaluated, Hib vaccine was shown to be cost effective, although the vaccine is not yet cost saving based on pentavalent vaccine prices in excess of US$3 per dose. Future issues include monitoring for serotype replacement and the effects of the HIV epidemic, evaluating the usefulness of a booster dose or new vaccine schedules and working to lower vaccine prices.