Chronic hepatitis B contact tracing in metropolitan Perth
Chronic hepatitis B (CHB) is associated with significant morbidity and mortality. People with CHB are a potential source of disease transmission.
Contacts of people with CHB are a national priority population for hepatitis B testing and vaccination. The Western Australian Department of Health recommends that:
- all household and sexual contacts of CHB cases be tested for hepatitis B infection
- non-immune household and sexual contacts be offered free hepatitis B immunisation1
- metropolitan public health units (PHUs) write to notifying doctors offering free hepatitis B vaccination for non-immune household and sexual contacts and assistance with contact tracing.
The success rate of contact tracing was audited by the Department which surveyed the GPs of 31 randomly selected patients notified with CHB between the 1 September 2011 and 1 September 2012. It interviewed 40 randomly selected patients notified with CHB during the same time period. Successful contact tracing was defined as:
- contacts who, on testing, were immune or infected
- contacts who were tested and completed a course of hepatitis B vaccination.
Data were collected in March 2013 to allow at least 6 months for contacts to be traced and complete a hepatitis B vaccination course.
The contact tracing success rate was 75% overall and was found to be similar in adult and child contacts. Success rates for nurse (used by one state government-funded clinic), doctor and patient-facilitated contact tracing were 100% (19/19), 60% (6/10) and 56% (10/18), respectively.
More than three-quarters of doctors (77%) remembered receiving a letter and/or phone call from a PHU with advice on contact tracing, and 74% knew that the Department provided free vaccines for contacts.
Two patients with CHB did not disclose their CHB status to their household contacts because they were students in shared accommodation. Under the current operational directive1, no distinction is made between household contacts who are sexual contacts and/or family members (who are at risk of contracting hepatitis B from the case) and adult housemates to whom the case is no more likely to transmit hepatitis B than to a workmate. Accurate assessment of contacts could increase contact-tracing efficiency through focusing resources on people whose type of contact with the case puts them at risk of contracting hepatitis B.
Nurse-facilitated contact tracing had the highest success rate. However, this option may not be feasible in private practice because contact tracing involves telephoning and/or sending letters to people who may not be patients of the case's GP and therefore do not generate Medicare payments. There were 463 CHB notifications in metropolitan WA during the one-year audit timeframe, meaning that most of WA's 9436 doctors would only be likely to notify a case every few years. Given the infrequent nature of this occurrence, doctors and nurses may feel unskilled at contact tracing. These structural barriers in private practice underscore the importance of PHU resources and expertise continuing to be available for doctors who require assistance with contact tracing.
- Department of Health, Western Australia. Hepatitis B vaccination program. 2009 Operational Directive/IC No: OD 0237/09.