Tracking the uptake of outcomes of hepatitis B virus testing using laboratory data in Victoria, 2011-16: A population-level cohort study

Background: A priority area in the 2016 Victorian Hepatitis B Strategy is to increase diagnostic testing. This study describes hepatitis B testing and positivity trends in Victoria between 2011 and 2016 using data from a national laboratory sentinel surveillance system. Methods: Line-listed diagnostic and monitoring hepatitis B testing data among Victorian individuals were collated from six laboratories participating in the Australian Collaboration for Coordinated Enhanced Sentinel Surveillance (ACCESS) of sexually transmissible infections and blood-borne viruses. Diagnostic tests included hepatitis B surface antigen (HBsAg)-only tests and guideline-based hepatitis B tests (defined as a single test event for HBsAg, hepatitis B surface antibody and hepatitis B core antibody). Using available data, the outcomes of testing and/or infection were further classified. Measures reported include the total number of HBsAg and guideline-based tests conducted and the proportion positive, classified as either HBsAg positive or chronic hepatitis B infection. Results: The number of HBsAg tests decreased slightly each year between 2011 and 2016 (from 91 043 in 2011 to 79 664 in 2016; P < 0.001), whereas the number of guideline-based hepatitis B tests increased (from 8732 in 2011 to 16 085 in 2016; P <0.001). The proportion of individuals classified as having chronic infection decreased from 25% in 2011 to 7% in 2016, whereas the proportion classified as susceptible and immune due to vaccination increased (from 29% to 39%, and from 27% to 34%, respectively; P < 0.001). Conclusions: The study findings indicate an increased uptake of guideline-based hepatitis B testing. The ongoing collection of testing data can help monitor progress towards implementation of the Victorian Hepatitis B Strategy