Hepatitis C transmission on the north coast of New South Wales: explaining the unexplained.

OBJECTIVE

To determine the routes of hepatitis C virus (HCV) transmission in an Australian community.

DESIGN

Questionnaire-based, cross-sectional survey of notified HCV cases.

SUBJECTS AND

SETTING

All cases notified to the New South Wales North Coast Public Health Unit between 1 January 1993 and 30 September 1994.

OUTCOME MEASURES: Frequency of potential transmission exposures (parenteral and sexual); most likely primary exposure; HCV infection rates in sexual partners and offspring.

RESULTS

467 subjects responded (47% of resident cases). Of these, all but one reported actual or potential blood exposures (injecting drug user [IDU], 85%; IDU with sharing of injection equipment, 76%; pre-1990 blood transfusions, 6%; other blood exposures, 8%). Most subjects reported multiple exposures and none reported sexual contact as the only potential exposure. Of 233 sexual partners tested for HCV, 83 were positive; 54 of these were questioned and all had other parenteral exposures. Only three children out of 91 children tested were positive for HCV (two expressing maternal antibodies).

CONCLUSIONS

In contrast with previous studies, possible HCV transmission modes were identified for almost all respondents. Most respondents in this community were IDUs. Non-parenteral transmission appeared minimal. Novel approaches to preventing HCV transmission in IDUs are needed.