Aspectos epidemiológicos da infecçào por Haemophilus influenzae tipo b / Epidemiologic aspects of Haemophilus influenzae type b infection

O objetivo do presente trabalho foi revisar o papel do Haemophilus influenzae tipo b (Hib) como um dos patogenos mais importantes implicados em doencas infecciosas invasivas, especialmente nos 2 primeiros anos de vida. Nos paises em desenvolvimento, o H. Influenzae chega a causar 30 por cento dos casos de pneumonia com cultura positiva e de 20 a 60 por cento dos casos de meningite bacteriana. No presente estudo, dados epidemiologicos do Brasil foram comparados com dados internacionais obtidos em bancos de dados (Medline, 1966 a 1995; LILACS, 1982 a 1995; Thesis databank, 1980- a 1995; e Dissertation abstracts, 1988 a 1994). Analisamos o coeficiente de incidencia do Hib no Brasil por estado e por faixa etaria, com estratificacao inclusive para o 1o. ano de vida. A meningite foi utilizada como marcador do coeficiente de incidencia devido as dificuldades para obter material adequado para a identificacao do microoganismo nos outros quadors, como pneumonia, osteomielite, epiglotite ou endocardite. Nossa analise revelou que os dados nacionais mascaram a incidencia e a letalidade regionais do H. influenzae: por exemplo, em 1991, a incidencia no Brasil foi de 18,4 em 100.000 criancas menores de 1 ano; no mesmo periodo, a incidencia no Distrito Federal foi de 175 em 100.000 criancas entre 4 e 6 meses. Alem disso, a letalidade na regiao Norte foi de 35 por cento em 1987, contra 22 por cento para o Brasil como um todo. Nosso estudo abre a discussao sobre aspectos epidemiologicos relevantes das infeccoes por Hib e sobre o custo-beneficio da profilaxia e vacinacao nas faixas etarias de maior risco

Vacunación contra Haemophilus influenzae tipo b en el Uruguay : experiencia e impacto / Vaccination against Haemophilus influenzae type b in Uruguay : experience and impact

Between 1979 and 1994, epidemiological surveillance of meningitides in Uruguay showed a progressive increase in suppurative meningitides due mainly to Neisseria meningitidis and Haemophilus influenzae type b (Hib). The cases were concentrated in children under 5; however, among the cases caused by Hib, 70 per cent affected children from 1 to 11 months old. Facing this situation, the Ministry of Public Health resolved, as of August 1994, to include the Hib vaccine in the country's Expanded Program on Immunization, which has been in place since 1982. The Hib vaccination is done without charge and is obligatory for all children under 5 years of age. It is done using the following series of vaccinations: a) three doses, given at 2, 4, and 6 months, with a booster dose at age 1; b) children from 7 to 11 months old receive two doses two monts apart and a booster dose a year later; and c) a single dose for children 12 months to 4 years old. Between August and December 1994 a coverage rate of 76.6 per cent was reached among children between 2 months and 4 years old, and the coverage has remained above 80 per cent in the new cohorts. In Uruguay, this vaccination strategy had a spectacular impact on morbidity and mortality due to meningitides caused by Hib. One of the results was that the incidence of 15.6 per 100 000 registered in children under 5 in the prevaccination years declined to 0.03 per 100 000 in 1996

Introducción de la vacuna conjugada contra Hib en Chile y Uruguay / Introducing Hib conjugate vaccine in Chile and Uruguay

In some countries, the invasive disease caused by Haemophilus influenzae type b (Hib) has been practically eliminated thanks to vaccination. However, in much of the developing world, meningitides and pneumonias caused by these bacteria continue to be a major cause of childhood morbidity and mortality, as well as high hospitalization costs. Because safe and effective conjugate vaccines are now available, the Special Program for Vaccines and Immunization of the Pan American Health Organization has recommended introducting them into the regular vaccination regimen of as many countries as possible. This has been done in Chile and Uruguay, where the Hib vaccine now forms part of the regular vaccination routine. When the vaccine was being introduced, both countries had difficulties they could have avoided if they had known of the experiences of other nations. Therefore, these two countries now offer the lessons they learned to other nations considering introducing the vaccine into their immunization programs. The most important lessons were to: strengthen the epidemiological surveillance system sufficiently in advance of introducing the vaccine; with the support of scientific societies, present the technical information that justifies introducing the vaccine; seek community baking and acceptance; precisely establish in advance the presentation and dosage of the vaccine that is most appropriate for the country; and be certain to have the political and legal decisions needed to ensure the continuity of Hib vaccination in the future