Hepatitis C virus seroprevalence in defined populations in New Zealand: data from a general practice-based screening programme.

Aim: To assess the hepatitis C virus (HCV) seroprevalence data for defined regions in New Zealand.

Methods: Email or mobile phone text invitations were sent out to adults enrolled with three participating general practices in different parts of New Zealand. Patients who provided informed consent were instructed to self-present for HCV blood tests. Patients with positive HCV antibodies had reflex testing of HCV antigen and ribonucleic acid (RNA) viral load.

Results: In total, 26,247 invitations were issued. Of these, 1,368 (5.2%) people gave informed consent and 1,021 patients (3.9%) had HCV blood tests. Ten out of 1,021 (0.98%; 95% confidence interval [CI] 0.51-1.82%) tested positive for HCV antibodies, of whom two (0.2%; 95% CI <0.01-0.76%) had positive antigen and elevated RNA viral load. The proportion of NZ Māori and Pacific people was low, at 3.8% and 0.4%, respectively. Volunteers with a high deprivation index were under-represented (3% from New Zealand Index of Deprivation deciles 9 and 10).

Conclusions: The HCV viraemia prevalence in this general practice-based screening programme is 0.2%, which is lower than previous estimates. This may have implications for appropriate resource allocations and the determination of the best strategies to find new HCV infections. Participation rates of people with high deprivation indexes or who were NZ Māori and Pacific people were low, suggesting that a tailored screening approach is needed.