Spatiotemporal proximity of rubella cases to the occurrence of congenital rubella syndrome in Yogyakarta, Indonesia.

INTRODUCTION

Rubella infection during early pregnancy may cause fatal consequences such as congenital rubella syndrome (CRS). The incidence rate (IR) of CRS confirmed cases in Yogyakarta, Indonesia between July 2008 and June 2013 was high at 0.05 per 1,000 live births. This study aimed to discover the spatiotemporal pattern of rubella and CRS and also identify whether the proximity of rubella cases was associated with the occurrence of CRS cases.

METHODS

This observational research used a spatiotemporal approach. We obtained CRS and rubella surveillance data from Dr. Sardjito Hospital, Provincial, and District Health Offices in Yogyakarta, Indonesia during January-April 2019. The home addresses of rubella and CRS cases were geocoded using the Global Positioning System. Average of the nearest neighbour and space-time permutation analyses were conducted to discover the spatiotemporal patterns and clusters of rubella and CRS cases.

RESULTS

The peak of rubella cases occurred in 2017 (IR: 22.3 per 100,000 population). Twelve confirmed cases of CRS were found in the 2016-2018 period (IR: 0.05 per 1,000 live births). The occurrence of CRS in Yogyakarta was detected 6-8 months after the increase and peak of rubella cases. The spatiotemporal analysis showed that rubella cases were mostly clustered, while CRS cases were distributed in a dispersed pattern. Rubella cases were found within a buffer zone of 2.5 km from any CRS case.

CONCLUSIONS

Rubella cases were spatiotemporally associated with the occurrence of CRS in Yogyakarta. We recommend strengthening the surveillance system of CRS and rubella cases in order to contain any further spreading of the disease.