Reduction of meningitis and impact on under-5 pneumonia after introducing the Hib vaccine in the Kingdom of Tonga.
OBJECTIVE
To document the impact of Hib vaccine on Haemophilus influenzae (Hi) invasive disease, meningitis and inpatient pneumonia in children under 5 in the Kingdom of Tonga.


METHODS
Cases of meningitis and pneumonia were sourced from the paediatric discharge book from 1 January 2000 to 2 November 2007 and from computerised discharge records from Vaoila Hospital on the island of Tongatapu where approximately 70% of the total population resides. Laboratory-confirmed cases were sourced from the microbiology laboratory register over the same period.


RESULTS
Prior to the introduction of Hib vaccine in 2005, there were, on average, 5.6 cases of invasive Hi disease per year. In the 22 months after Hib vaccine introduction, there was only one case of invasive Hi disease. This corresponds to a fall in the annual incidence of invasive Hib disease from 54.3 to 5.1/100,000 children under 5 years of age. The annual incidence of inpatient pneumonia has fallen by 28.3% from 1007.6 to 722.8/100,000 children under 5 in the 22 months after introducing the vaccine.


CONCLUSIONS
Hib vaccine has reduced invasive Hi disease and Hi meningitis in Tonga. The reduction in inpatient pneumonia is more likely a reflection of annual fluctuations in viral pneumonia than of a reduction in Hib pneumonia, but ongoing surveillance is recommended.
Russell
F M
FM
Centre for International Child Health, Department of Paediatrics, University of Melbourne, Victoria, Australia. fionarussell@connect.com.fj
Fakakovi
T
T
Paasi
S
S
Ika
A
A
Mulholland
E K
EK
D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control*; D005260:Female; D018073:Haemophilus Vaccines / Q000008:administration & dosage*; D019741:Haemophilus influenzae type b / Q000276:immunology*; D006801:Humans; D017589:Immunization Programs; D015994:Incidence; D007223:Infant; D008297:Male; D008583:Meningitis, Haemophilus / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control*; D018410:Pneumonia, Bacterial / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control*; D012189:Retrospective Studies; D014058:Tonga
D018073:Haemophilus Vaccines