Spectrum and burden of severe Haemophilus influenzae type b diseases in Asia

The validity of the commonly held view that Haemophilus influenzae type b ( Hib) diseases are rare in Asia is challenged in this article by a thorough analysis of the data available, often in languages other than English. The entire spectrum of Hib disease, not only meningitis, was taken into account , and over 100 reports from 25 countries were explored. Hib was the leading agent among nontuberculous childhood meningitis cases in two-thirds of 48 studies from 22 countries. Data from six countries showed that all the clas sical manifestations of invasive Hib diseases are also found in Asia, excep t epiglottitis, which was nearly absent. In Hang Kong Special Administrativ e Region of China Hib disease is rare, but otherwise the incidences seemed not to deviate much from those in Europe until recently, around 25 per 100 000 for meningitis and at least 40 per 100 000 per year for the classical H ib manifestations combined at age 0-4 years. In total, more than 200 000 ca ses of Hib disease are estimated to occur annually in Asia. Because nonbact eraemic Hib pneumonia remains mostly undetected, the total burden is probab ly significantly greater. The issue will be fully elucidated only by prospe ctive epidemiological and clinical studies, but awaiting them should not de lay large-scale vaccinations against Hib throughout Asia.