Hepatitis B prophylaxis in adolescents who present for examination after alleged sexual assault

In Australia, the risk of hepatitis B virus (HBV) transmission from single sexual contact is low. This, combined with assumed widespread immunity from vaccination, has resulted in a lack of clarity surrounding the necessity for hepatitis B post-exposure prophylaxis following recent sexual assault.

This retrospective audit was conducted through the Victorian Forensic Paediatric Medical Service (VFPMS) at the Royal Children's Hospital, Melbourne, Australia. Subjects were patients aged 13-17 years who presented to VFPMS between 1 January 2007 and 31 December 2016 for forensic medical examination following an alleged penetrative sexual assault. Data collected included subject demographics, immunisation status, route of potential HBV exposure, time between alleged sexual assault and presentation, whether HBsAb levels were tested and the results and whether HBV prophylaxis was administered to the subject and its timing.

A total of 2121 records were reviewed, and 420 subjects were found to be eligible for inclusion; 26.2% (n = 110) had HBsAb levels measured at initial presentation. Of these 110 subjects, 45.5% (n = 50) had titre levels less than 10 (deemed to be non-protective) and were therefore vulnerable to HBV infection. Of the 420 subjects, 4.5% (n = 19) received HBV prophylaxis as a result of their assessment.

Results suggest that a high proportion of Australian adolescents presenting following recent sexual assault may be at risk of hepatitis B infection. Very few received timely prophylaxis. Follow-up attendance rates were poor. Administration of the hepatitis B booster vaccine at the point of contact may reduce the risk of HBV infection in this group of adolescents.