Evaluation of using ICD-10 code data for respiratory syncytial virus surveillance

Background Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory tract infection (ALRI) in young children. ICD-10-based syndromic surveillance can transmit data rapidly in a standardized way. Objectives We investigated the use of RSV-specific ICD-10 codes for RSV surveillance. Methods We performed a retrospective descriptive data analysis based on existing ICD-10-based surveillance systems for ALRI in primary and secondary care and a linked virological surveillance in Germany. We described RSV epidemiology and compared the epidemiological findings based on ICD-10 and virological data. We calculated sensitivity and specificity of RSV-specific ICD-10 codes and in combination with ICD-10 codes for acute respiratory infections (ARI) for the identification of laboratory-confirmed RSV infections. Results Based on the ICD-10 and virological data, epidemiology of RSV was described, and common findings were found. The RSV-specific ICD-10 codes had poor sensitivity 6% (95%-CI: 3%-12%) and high specificity 99.8% (95%-CI: 99.6%-99.9%). In children <5 years and in RSV seasons, the sensitivities of RSV-specific ICD-10 codes combined with general ALRI ICD-10 codes J18.-, J20.- and with J12.-, J18.-, J20.-, J21.-, J22 were moderate (44%, 95%-CI: 30%-59%). The specificities of both combinations remained high (91%, 95%-CI: 86%-94%; 90%, 95%-CI: 85%-94%). Conclusions The use of RSV-specific ICD-10 codes may be a useful indicator to describe RSV epidemiology. However, RSV-specific ICD-10 codes underestimate the number of actual RSV infections. This can be overcome by combining RSV-specific and general ALRI ICD-10 codes. Further investigations are required to validate this approach in other settings.