Anton Widjaya

Incidences of vaccine-preventable Haemophilus influenzae type b pneumonia and meningitis in Indonesian children: hamlet-randomised vaccine-probe trial.

BACKGROUND Most studies of Haemophilus influenzae type b (Hib) disease in Asia have found low rates, and few Asian countries use Hib vaccine in routine immunisation programmes. Whether Hib disease truly is rare or whether many cases remain undetected is unclear. METHODS To estimate incidences of vaccine-preventable Hib pneumonia and meningitis among children younger than 2 years in Lombok, Indonesia, during 1998-2002, we undertook a hamlet-randomised, controlled, double-blind vaccine-probe study (818 hamlets). Children were immunised (WHO schedule) with diphtheria, tetanus, pertussis (DTP) or DTP-PRP-T (Hib conjugate) vaccine. Vaccine-preventable disease incidences were calculated as the difference in rates of clinical outcomes between DTP and DTP-PRP-T groups. Analyses included all children who received at least one vaccine dose. FINDINGS We enrolled 55073 children: 28147 were assigned DTP-PRP-T and 26926 DTP. The proportion of pneumonia outcomes prevented by vaccine ranged from less than 0 to 4.8%. Calculated incidences of vaccine-preventable Hib disease (per 10(5) child-years of observation) for outcome categories were: substantial alveolar consolidation or effusion, less than zero (-43 [95% CI -185 to 98]); all severe pneumonia, 264 (95% CI less than zero to 629); all clinical pneumonia, 1561 (270 to 2853); confirmed Hib meningitis, 16 (1.4 to 31); meningitis with cerebrospinal-fluid findings consistent with a bacterial aetiology, 67 (22 to 112); and admission for suspected meningitis or presenting to a clinic with convulsions, 158 (42 to 273). INTERPRETATION Hib vaccine did not prevent the great majority of pneumonia cases, including those with alveolar consolidation. These results do not support a major role for Hib vaccine in overall pneumonia-prevention programmes. Nevertheless, the study identified high incidences of Hib meningitis and pneumonia; inclusion of Hib vaccine in routine infant immunisation programmes in Asia deserves consideration.

Hepatitis B vaccine freezing in the Indonesian cold chain: evidence and solutions

OBJECTIVES To document and characterize freezing temperatures in the Indonesian vaccine cold chain and to evaluate the feasibility of changes designed to reduce the occurrence of freezing. METHODS Data loggers were used to measure temperatures of shipments of hepatitis B vaccine from manufacturer to point of use. Baseline conditions and three intervention phases were monitored. During each of the intervention phases, vaccines were removed progressively from the standard 2-8 degrees C cold chain. FINDINGS Freezing temperatures were recorded in 75% of baseline shipments. The highest rates of freezing occurred during transport from province to district, storage in district-level ice-lined refrigerators, and storage in refrigerators in health centres. Interventions reduced freezing, without excessive heat exposure. CONCLUSIONS Inadvertent freezing of freeze-sensitive vaccines is widespread in Indonesia. Simple strategies exist to reduce freezing - for example, selective transport and storage of vaccines at ambient temperatures. The use of vaccine vial monitors reduces the risk associated with heat-damaged vaccines in these scenarios. Policy changes that allow limited storage of freeze-sensitive vaccines at temperatures >2-8 degrees C would enable flexible vaccine distribution strategies that could reduce vaccine freezing, reduce costs, and increase capacity.

Climatic, temporal, and geographic characteristics of respiratory syncytial virus disease in a tropical island population

Respiratory syncytial virus (RSV) is an important cause of morbidity in children worldwide, although data from equatorial regions are limited. We analysed climatic, spatial, and temporal data for children presenting to hospitals in Lombok island, Indonesia with clinical pneumonia. During the study period, 2878 children presented and 741 RSV cases were identified. In multivariate analysis with an 8-day lag, occurrence of rain was associated with 64% higher incidence of RSV disease [incidence rate ratio (IRR) 1.64, 95% confidence interval (CI) 1.13-2.38]. A 1% rise in mean relative humidity and 1 degree C increase in mean air temperature was associated with a 6% (IRR 1.06, 95% CI 1.03-1.10) and 44% (IRR 1.44, 95% CI 1.24-1.66) increase in RSV cases, respectively. Four statistically significant local clusters of RSV pneumonia were identified within the annual island-wide epidemics. This study demonstrates statistical association of monsoon-associated weather in equatorial Indonesia with RSV. Moreover, within the island-wide epidemics, localized RSV outbreaks suggest local factors influence RSV disease.

Streptococcus pneumoniae Nasopharyngeal Carriage Prevalence, Serotype Distribution, and Resistance Patterns among Children on Lombok Island, Indonesia

Few data exist on childhood pneumococcal carriage prevalence, serotype distribution, and resistance patterns for Indonesia, the worlds fourth most populous country. During August 1997, nasopharyngeal samples were collected from a population-based, island-wide sample of 484 healthy children (age, 0-25 months) from Lombok Island, Indonesia. Two hundred twenty-one pneumococcal isolates were identified, for a carriage prevalence of 48%; 66% of isolates were of serogroup or serotype 6, 23, 15, 33, or 12. All isolates were susceptible to penicillin and cefotaxime. Twelve percent of the isolates were nonsusceptible to sulfamethoxazole or chloramphenicol and 4% were nonsusceptible to both of these drugs. Nonsusceptible organisms were most frequently serogroup or serotype 6, 12, and 33. Lombok has a moderate pneumococcal carriage prevalence and a relatively low proportion of resistant isolates. At least 3 of the 5 most common serogroups and serotypes and 2 of the 3 most common nonsusceptible serogroups and serotypes are not included in the current 7-valent pneumococcal conjugate vaccine.

The costs of home delivery of a birth dose of hepatitis B vaccine in a prefilled syringe in Indonesia

OBJECTIVE To provide global policy-makers with decision-making information for developing strategies for immunization of infants with a birth dose of hepatitis B vaccine, this paper presents a retrospective cost analysis, conducted in Indonesia, of delivering this vaccine at birth using the Uniject prefill injection device. METHODS Incremental costs or cost savings associated with changes in the hepatitis B immunization programme were calculated using sensitivity analysis to vary the estimates of vaccine wastage rates and prices for vaccines and injection devices, for the birth dose of hepatitis B vaccine. FINDINGS The introduction of hepatitis B vaccine prefilled in Uniject (HB-Uniject) single-dose injection devices for use by midwives for delivering the birth dose is cost-saving when the wastage rate for multidose vials is greater than 33% (Uniject is a trademark of BD, Franklin Lakes, NJ, USA). CONCLUSION The introduction of HB-Uniject for birth-dose delivery is economically worthwhile and can increase coverage of the critical birth dose, improve resource utilization, reduce transmission of hepatitis B and promote injection safety.

A population-based survey of Haemophilus influenzae type b nasopharyngeal carriage prevalence in Lombok Island, Indonesia

BACKGROUND The Haemophilus influenzae type b (Hib) nasopharyngeal carriage prevalence and invasive disease incidence rates are unknown in Indonesia; consequently Hib vaccine is not included in the routine vaccine schedule. METHODS To determine carriage prevalence we conducted a population-based, island-wide prospective study of a systematic sample of 484 children 0 to 2 years of age in Lombok, Indonesia. We conducted a risk factor questionnaire and determined serotypes and antibiotic sensitivity patterns. RESULTS We identified 155 H. influenzae isolates, of which 22 were type b and 12 were encapsulated but not type b. The age- and population-weighted Hib carriage prevalence, adjusted for the sampling design, was 4.6% (95% confidence interval, 3.7 to 5.5%). Children younger than 6 months of age had a carriage prevalence less than one-half that of older children, and carriage varied within the four administrative regions of the island; otherwise no risk factors for Hib carriage were identified. All Hib specimens were sensitive to ampicillin and 20 (91%) were sensitive to chloramphenicol. CONCLUSIONS The Hib carriage prevalence in Lombok is similar to that found in developed countries before vaccine introduction. This suggests that further studies should proceed to determine whether Lombok has invasive disease rates as high as those that justified vaccine introduction in developed countries.

Outcome and extent of disability following Japanese encephalitis in Indonesian children.

OBJECTIVES The study aimed to assess outcome, including level of disability, following Japanese encephalitis (JE) in children in Indonesia. METHODS A cohort of children diagnosed with laboratory-confirmed JE from January 2005 to August 2006 was followed-up, with disability measured at least 4 months after discharge from hospital. An assessment tool that can be used to rapidly determine practical level of disability and the likelihood that a child will be able to live independently after illness, the Liverpool Outcome Score, was used. RESULTS Of 72 children with JE, determination of outcome was possible for 65 (90%). Sixteen died in hospital or before follow-up assessment (25%). Sixteen children (25%) had severe sequelae, indicating their function was impaired enough to likely make them dependent. Five (7%) had moderate sequelae and 12 (18%) had minor sequelae. The remaining 16 children (25%) were considered to have recovered fully. CONCLUSIONS Half of the children with JE either died or were left with serious disabilities likely to impair their ability to lead independent lives, demonstrating the severe impact of JE. Immunization can effectively prevent JE, and an immunization program could avert some of the economic and social burden of JE disease in Indonesia.

Reuse Prevention Syringes for Reconstitution of Lyophilized Vaccines: Operational Study and UNICEF Plans for Expanding Introduction

Abstract Since the 1990s, the United Nations Childrens Fund has encouraged injection safety for immunizations through bundling vaccines with appropriate amounts of supporting equipment and by supplying autodisable (AD) syringes for injections. However, poor vaccine reconstitution practices continue to be reported worldwide. By 2009, UNICEF will begin to phase out the distribution of standard disposable syringes for vaccine reconstitution and replace them with reuse prevention (RUP) syringes, with a full transition expected by the end of 2010. A field evaluation in Indonesia was conducted to identify introduction requirements, issues with healthcare worker training and acceptance, and RUP syringe performance and safety. Managers and health workers felt that RUP syringes improved injection safety and fit easily into country logistical systems. Healthcare workers felt they were intuitive to use, but recommended special training. The integration of RUP reconstitution syringes by UNICEF could increase injection safety by preventing the reuse of syringes and reducing vaccine contamination.