Vacunación contra Haemophilus influenzae tipo b en el Uruguay: experiencia e impacto

Abstract

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% 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 months 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% was reached among children between 2 months and 4 years old, and the coverage has remained above 80% 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.

Impact of the Haemophilus influenzae type b vaccination program on HIB meningitis in Brazil

“…In evaluating the impact of the HIB vaccination program in children less than 5 years of age worldwide, several authors have presented similar results on the decrease in incidence levels, using time intervals in the pre-and postvaccination periods that were similar to those in the present study 3,24,29,30,31 . In Brazil, no studies have been published with large time series to evaluate the incidence and mortality rates in the pre-vaccination period.…”

“…However, other factors must be taken into account when new cases appear, such as deficient product storage or errors in administering the vaccine. According to the literature, the small number of new cases in regions where the HIB vaccine has been introduced have occurred in individuals with an incomplete vaccination schedule, age groups that did not receive the vaccine, or non-immunized persons 24,25,26,27 . Therefore, efforts to control invasive HIB disease continue to be encouraged by creating collective awareness about the disease's severity, effective surveillance programs, and expansion of vaccine coverage 25,28 .…”

<i>Haemophilus influenzae</i> type b vaccination: long-term protection

“…Dados de vigilância nesses países detectaram declínio superior a 80% na meningite por Hib logo após a introdução da vacina 14,26,29,33 . Na América Latina, avaliações do impacto da vacinação nas meningites foram realizadas em Cuba, Colômbia, Uruguai, Chile e Brasil 31 , mostrando que as taxas de incidência de meningite por Hib no período pós-vacinal declinaram de 40 a 95%, comparadas ao período pré-vacinação, conforme mostrado na Tabela 1 22,[34][35][36][37][38][39][40][41][42] .…”

Intervenções para reduzir a mortalidade infantil pré-escolar e materna no Brasil

“…No Uruguai, a meningite causada pelo Hib foi praticamente eliminada através da vacinação 98 . Presumindo-se que 30% dos casos de meningite no Brasil são causados pelo Hib r , e que a eficácia da vacina é de 95%, 7,0% de todas as mortes por outras infecções (0,6% da mortalidade total de menores de cinco anos) seriam evitadas se fosse atingida uma cobertura vacinal de 80%.…”