World-wide epidemiology of Haemophilus influenzae meningitis; industrialized versus non-industrialized countries.

The epidemiology of Haemophilus influenzae meningitis in non-industrialized areas shows considerable differences from that in the industrialized world. The incidence rates among Alaskan Eskimos, Navaho and White Mountain Indians, Australian Aboriginals and among populations in Africa such as Gambians and Senegalese are three- to fourfold higher than those in the USA and up to ten times higher than those in Europe. The peak age in populations with a high incidence is around 5 to 6 months of age compared to 9 months of age in other countries. The case fatality rate (CFR) is not related to the state of industrialization but seems to be more dependent on the accessibility of health care facilities. Africa the CFR is about ten times higher than that seen elsewhere. Apart from other dissimilarities such as the pattern of serotypes causing disease and the transmission rate, the epidemiology of Hib disease is sufficiently different from industrialized areas that it demands a thorough testing of a conjugated Hib vaccine before it can be introduced on a large scale in populations in non-industralized areas.