Impact of Haemophilus influenzae type b conjugate vaccine on bacterial meningitis in the Dominican Republic.
OBJECTIVE
Widespread use of Haemophilus influenzae type b (Hib) vaccines has dramatically reduced the burden of Hib disease throughout the Americas. Few studies have evaluated the impact of Hib vaccination on non-culture-confirmed disease. This study analyzed trends in probable bacterial meningitis before and after the introduction of Hib vaccine in the Dominican Republic and estimated vaccine effectiveness against Hib meningitis.


METHODS
Meningitis cases among children < 5 years of age were identified from admission records of the main pediatric hospital in Santo Domingo during 1998-2004. Laboratory criteria were used to classify meningitis cases with probable bacterial etiology; confirmed cases had positive bacterial culture or antigen detection in cerebrospinal fluid. Cumulative incidence rates of confirmed and probable bacterial meningitis were calculated for children living in the National District. Confirmed cases of Hib meningitis were enrolled in a case-control study with age- and neighborhood-matched control children to calculate vaccine effectiveness.


RESULTS
Before vaccine introduction, annual rates of meningitis with probable bacterial etiology were 49 cases per 100 000 children < 5 years old; Hib accounted for 60% of confirmed bacterial cases. During 2002-2004, after vaccine introduction, annual rates of probable bacterial meningitis were 65% lower at 16 cases per 100 000, and Hib accounted for 26% of confirmed cases. Rates of Hib meningitis and probable bacterial meningitis with no determined etiology declined by 13 and 17 cases per 100 000, respectively.


CONCLUSIONS
Introduction of Hib vaccine substantially reduced the incidence of confirmed and probable bacterial meningitis in the Dominican Republic. The estimated impact of Hib vaccination was twice as great when non-culture-confirmed disease was included.
Lee
Ellen H
EH
Division of Bacterial Diseases, National Center for Immunizations and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. ellelee@hotmail.com
Corcino
Miriam
M
Moore
Arelis
A
Garib
Zacarias
Z
Peña
Chabela
C
Sánchez
Jacqueline
J
Fernández
Josefina
J
Feris-Iglesias
Jesús M
JM
Flannery
Brendan
B
D016667:Bacterial Capsules / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D004293:Dominican Republic / Q000453:epidemiology; D018073:Haemophilus Vaccines / Q000008:administration & dosage*; D019741:Haemophilus influenzae type b / Q000302:isolation & purification*; D006801:Humans; D008583:Meningitis, Haemophilus / Q000453:epidemiology* / Q000382:microbiology*
D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine