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Vaccine. 1991 Jun;9 Suppl:S5-9; discussion S25.

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

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Department of Medical Microbiology, University of Amsterdam, The Netherlands.


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.


The incidence, case fatality rate (CFR), age distribution, serotype distribution and transmission of Haemophilus influenzae meningitis worldwide are reviewed. This organism is a commensal in the throat, but serotype b can become invasive and causes the majority of meningitis disease in infants in most countries. The incidence is estimated at 47/100,000 in the US, and 20-30/100,000 in Europe for children 5 years. In non-industrialized settings, data are available for Alaska and The Gambia, where incidence is 60/100,000 children 5. In Africa the peak age is 6 months of age, compared to 8-9 months is the West, where 60% of cases occur in adults as well. The CFR ranges from 1.95-5% in the West, a function of hospital facilities, but is reported to be 26% in Nigeria and 57% in Egypt. H. influenzae serotype b predominates in most countries. Only 3 common outer membrane protein antigens are common, but the lipopolysaccharide types vary widely. In West Africa serotype a is more prevalent, and in The Gambia an entirely different clone was isolated. The carriage rate appears to be low, around 2-4% in most communities, but in some closed communities, such as day care centers, up to 56% carriage has been found. It is theorized that introduction of new strains is the reason for infection of very young children in developing areas.

[Indexed for MEDLINE]

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