Abstract:
Haemophilus influenzae type b (Hib) infection occurs worldwide and is considered a major
childhood killer, causing severe forms of infection including meningitis, septicaemia and
pneumonia With the wide use of second generation conjugate Hib vaccmes, the countries
which introduced the vaccine in the westem hemisphere have almost eradicated the Hib
diseases. The availability of safe and effective vaccines highlights the need for accurate Hib
incidence data for making decisions on vaccine policy. The present study was planned with
the intention of accurately estimating Hib disease incidence in the district of Colombo, Sri
Lanka. The study consisted of a prospective, population based study of Hib infections in the
District of Colombo and a case control study to examine the association of Hib infection
with selected factors. All five hospitals in the district of Colombo with a consultant
paediatrician participated in the study. With the objective of describing the epidemiology of
Hib infections in the age group 0-5 years in the district of Colombo, the present study was
carried out during the year The study documented for the first time a community based
microbiological analysis of meningitis in infants and preschool children. All Hib infections
detected were that of type b and accounted for 50 percent of the aetiologically confirmed
meningitis. The next two common micro organIsms were Group B Streptococcus (23
percent ) and Streptococcus pneumoniae ( 13 percent). Hib meningitis constituted 84
percent of the Hib diseases. Almost 80 percent of the Hib meningitis cases occurred in the
age group below 24 months and 59 percent of all meningitis cases were below 12 months of
age. The highest incidence of Hib disease was in the 3-5 months age group. A biphasic
seasonality pattern of Hib disease incidence was demonstrated by the present study. Sri
Lanka has an extensive primary health care network and a well performing EPI programme.
Current DPT+HepB schedule of 2,4, 6 months further enhances the opportunity to introduce
the Hib vaccine as the disease is seen more in early infancy as demonstrated by the present
study
