Evaluation of the rubella surveillance system in South Africa, 2016-2018: A cross-sectional study.

backgroundRubella is a leading vaccine-preventable cause of birth defects. We conducted this study to evaluate the rubella surveillance system in South Africa from 2016 to 2018. The rubella surveillance system had not been evaluated since its inception; therefore, a formal evaluation is necessary to assess key attributes and to ascertain the extent to which the system achieves its objectives.

methodsWe conducted a cross-sectional study to assess the usefulness, simplicity, positive predictive value, timeliness, and data quality of the rubella surveillance system from 2016 to 2018. We reviewed retrospective rubella surveillance data and conducted a survey with key stakeholders of the system. We compiled a summary report from the survey and calculated the annualized detection rate of rubella and non-rubella febrile rash, positive predictive value, the proportion of complete records, and timeliness between the surveillance steps. We compared our results with recommended performance indicators from the 2015 revised World Health Organization African regional guidelines for measles and rubella surveillance.

resultsThe rubella surveillance system was useful but weak in terms of simplicity. The annualized detection rate of rubella febrile rash was 1.5 per 100,000 populations in 2016, 4.4 in 2017, and 2.1 in 2018. The positive predictive value was 29.1% in 2016, 40.9% in 2017, and 32.9% in 2018. The system did not meet the timeliness goal in the health facility component but met this goal in the laboratory component. The system had poor data quality, particularly in the health facility component.

conclusionsThe rubella surveillance system was useful, although it was not simple to use and had low PPV, poor timeliness, and poor data quality. Efforts should be made to improve the system's simplicity, PPV, timeliness, and data quality at the facility level.