Hepatitis A outbreaks among illicit drug users and their contacts in Queensland, 1997

Objective: To describe five outbreaks of hepatitis A virus (HAV) infection associated with illicit drug use during a statewide outbreak of HAV infecti on in Queensland. Design: Risk factor prevalence survey. Patients and setting: All 875 cases of HAV infection notified to Public Hea lth Units in Queensland in the 12 months to 30 November 1997. Main outcome measure: Type and prevalence of illicit drug use. Results: Risk factor assessment was completed for 804 cases (91.9%). We ide ntified five outbreaks of HAV infection linked to illicit drug use. These o utbreaks accounted for 24.6% (215/875) of all notified cases and 39% (190/4 82) of notified cases in the 15-34 years age group. The main type of illici t drug use in four of the five outbreaks was injecting drug use (74%; 118/1 60), while in the other outbreak it was sharing of smoking implements for m arijuana (38%; 21/55). Conclusion: Illicit drug use may be an under-recognised risk factor for HAV infection, particularly in young people. Faecal-oral transmission through poor personal hygiene, including sharing of implements for smoking marijuan a, is the most probable route of transmission in these drug-linked outbreak s. The role of contaminated drug and needle-sharing remains to be clarified .