Estimated incidence of influenza-associated severe acute respiratory infections in Indonesia, 2013-2016.

BACKGROUND: Indonesia's hospital-based Severe Acute Respiratory Infection (SARI) surveillance system, Surveilans Infeksi Saluran Pernafasan Akut Berat Indonesia (SIBI), was established in 2013. While respiratory illnesses such as SARI pose a significant problem, there are limited incidence-based data on influenza disease burden in Indonesia. This study aimed to estimate the incidence of influenza-associated SARI in Indonesia during 2013-2016 at three existing SIBI surveillance sites. METHODS: From May 2013 to April 2016, inpatients from sentinel hospitals in three districts of Indonesia (Gunung Kidul, Balikpapan, Deli Serdang) were screened for SARI. Respiratory specimens were collected from eligible inpatients and screened for influenza viruses. Annual incidence rates were calculated using these SIBI-enrolled influenza-positive SARI cases as a numerator, with a denominator catchment population defined through hospital admission survey (HAS) to identify respiratory-coded admissions by age to hospitals in the sentinel site districts. RESULTS: From May 2013 to April 2016, there were 1527 SARI cases enrolled, of whom 1392 (91%) had specimens tested and 199 (14%) were influenza-positive. The overall estimated annual incidence of influenza-associated SARI ranged from 13 to 19 per 100 000 population. Incidence was highest in children aged 0-4 years (82-114 per 100 000 population), followed by children 5-14 years (22-36 per 100 000 population). CONCLUSIONS: Incidence rates of influenza-associated SARI in these districts indicate a substantial burden of influenza hospitalizations in young children in Indonesia. Further studies are needed to examine the influenza burden in other potential risk groups such as pregnant women and the elderly.

Application of WHO's guideline for the selection of sentinel sites for hospital-based influenza surveillance in Indonesia.

BACKGROUND: A sentinel hospital-based severe acute respiratory infection (SARI) surveillance system was established in Indonesia in 2013. Deciding on the number, geographic location and hospitals to be selected as sentinel sites was a challenge. Based on the recently published WHO guideline for influenza surveillance (2012), this study presents the process for hospital sentinel site selection. METHODS: From the 2,165 hospitals in Indonesia, the first step was to shortlist to hospitals that had previously participated in respiratory disease surveillance systems and had acceptable surveillance performance history. The second step involved categorizing the shortlist according to five regions in Indonesia to maximize geographic representativeness. A checklist was developed based on the WHO recommended attributes for sentinel site selection including stability, feasibility, representativeness and the availability of data to enable disease burden estimation. Eight hospitals, a maximum of two per geographic region, were visited for checklist administration. Checklist findings from the eight hospitals were analyzed and sentinel sites selected in the third step. RESULTS: Six hospitals could be selected based on resources available to ensure system stability over a three-year period. For feasibility, all eight hospitals visited had mechanisms for specimen shipment and the capacity to report surveillance data, but two had limited motivation for system participation. For representativeness, the eight hospitals were geographically dispersed around Indonesia, and all could capture cases in all age and socio-economic groups. All eight hospitals had prerequisite population data to enable disease burden estimation. The two hospitals with low motivation were excluded and the remaining six were selected as sentinel sites. CONCLUSIONS: The multi-step process enabled sentinel site selection based on the WHO recommended attributes that emphasize right-sizing the surveillance system to ensure its stability and maximizing its geographic representativeness. This experience may guide other countries interested in adopting WHO's influenza surveillance standards for sentinel site selection.