Burden of invasive pneumococcal disease (IPD) in Sri-Lanka: Deriving a reasonable measure for vaccine introduction decision making.

PURPOSE: The lack of evidence on the disease burden has been an obstacle for decision-making on introducing pneumococcal vaccines in Sri-Lanka. Hence, the purpose of this study is to determine the incidence of invasive pneumococcal disease among children under five-years of age in Sri-Lanka's Colombo district. METHODS: In a community-based study, using a sample of 2310 children, we identified syndromes associated with pneumococcal disease (pneumonia, meningitis, sepsis). The estimates of annual cumulative incidence of invasive pneumococcal disease were derived by having applied proportions of laboratory confirmed invasive pneumococcal disease among all-cause syndromes associated with pneumococcal infection obtained from the hospital-based invasive bacterial disease sentinel surveillance and findings of the community-based study to population parameters of the district. The estimates of invasive pneumococcal pneumonia and sepsis based on low-sensitive, culture confirmation were adjusted by a correction factor. RESULTS: The annual cumulative incidence of all-cause clinical syndromes associated with pneumococcal disease (pneumonia, meningitis, sepsis) were 1.3, 0.52, 0.39 per 100 children, respectively. The estimate of adjusted, invasive pneumococcal disease cumulative incidence was 206.3 per 100,000 while estimates of pneumococcal pneumonia, meningitis and sepsis cumulative incidence were 147.9, 13.2 and 45.2 per 100,000 under-five children. CONCLUSION: Reasonable estimates of invasive pneumococcal disease could be derived by using incidence of clinical syndromes associated with pneumococcal disease obtained from population-based studies and proportion of pneumococcal infection among all-cause clinical syndromes associated with pneumococcal disease generated from hospital-based sentinel surveillance. These estimates may help informed decision-making on introduction of pneumococcal conjugated vaccine.

A cohort event monitoring to determine the adverse events following administration of mouse brain derived, inactivated Japanese Encephalitis vaccine in an endemic district in Sri Lanka.

Introduction of human immunization reduced Japanese Encephalitis (JE) cases dramatically in Sri Lanka. However, the increased reporting of adverse events following immunization (AEFI) affected vaccine acceptance by the community. Against this background, we describe the incidence of overall AEFI and incidence and profile of AEFI, thought to be causally related to the mouse-brain derived JE vaccine. A follow-up of 9798 vaccine recipients was performed for a period of two weeks post-vaccination. Parents self-recorded observed signs and symptoms. The self-records were collected by trained supervisors. All monitored children who manifested symptom/s were investigated in details by medical officers experienced in AEFI investigations within two weeks after ending the follow-up period. Using the results of the investigation, the causality assessment was performed. The estimated cumulative incidence rate of overall AEFI was 8.6 children per 100 immunizations. The same for observed AEFI consistent with causal association to the inactivated JE vaccine was 4.3 children (95% CI-3.9-4.7%) per 100 immunizations. The most frequent AEFI was fever (81%). The frequency of high fever (>102 °F) was 26%. Other major AEFI were body ache (22%) vomiting (21%), urticaria (19%), pruritus (5%), and headache (5%). Though 83% of children with AEFI thought to be causally related to the vaccine sought medical care, only 6.6% required hospitalizations. The incidence rate of AEFI in the cohort event monitoring was several-fold higher than that reported through the national AEFI surveillance system. The incidence rate of allergic manifestations among Sri-Lankan children approached what was reported for non-endemic settings and was higher than in other JE endemic populations elsewhere. Contrary to the belief of medical practitioners and the general public, incidence of seizures was low and vaccine related other neurological manifestations were absent.