Effectiveness of Haemophilus influenzae type B conjugate vaccine on prevention of pneumonia and meningitis in Bangladeshi children: a case-control study.
BACKGROUND
Few Asian countries have introduced Haemophilus influenzae type b (Hib) conjugate vaccine because of its cost and uncertainty regarding disease burden.


METHODS
To estimate the effectiveness of Hib conjugate vaccine in preventing pneumonia and meningitis in children age <2 years, an incident case-control study was conducted in a birth cohort of about 68,000 infants in Dhaka city, Bangladesh. DPT vaccine was systematically replaced by a combined Hib-DPT vaccine in selected immunization centers of the study area. Four matched community- and 2 hospital-controls were randomly selected for each confirmed case of pneumonia and meningitis from the study area.


RESULTS
About 35% of the infants received each of the 3 doses of Hib-DPT vaccine. There were 2679 children who had a chest roentgenogram. For 475 children, a radiologist and a pediatrician independently identified substantial alveolar consolidation. Following at least 2 doses of Hib vaccine, the preventable fractions [95% confidence intervals (CI)] using community and hospital controls were 17% (-10% to 38%) and 35% (13% to 52%) respectively. Of these 475 cases, 2 radiologists with the World Health Organization concurred with the findings for 343 patients, yielding preventable fractions of 34% (6% to 53%) and 44% (20% to 61%). Fifteen confirmed Hib meningitis cases were identified; the preventable fractions (95% CI) using community and hospital controls, respectively, were 89% (28% to 100%) and 93% (53% to 100%).


CONCLUSIONS
The study documented that significant fractions of pneumonia and meningitis in Bangladeshi children age <2 years can be prevented by the Hib conjugate vaccine.
Baqui
Abdullah H
AH
Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA. abaqui@jhsph.edu
El Arifeen
Shams
S
Saha
Samir K
SK
Persson
Larsåke
L
Zaman
K
K
Gessner
Bradford D
BD
Moulton
Lawrence H
LH
Black
Robert E
RE
Santosham
Mathuram
M
D001459:Bangladesh / Q000453:epidemiology; D016022:Case-Control Studies; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage; D005260:Female; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006801:Humans; D007223:Infant; D008297:Male; D008583:Meningitis, Haemophilus / Q000453:epidemiology / Q000517:prevention & control*; D011014:Pneumonia / Q000453:epidemiology / Q000517:prevention & control*; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology*
D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; D018074:Vaccines, Conjugate