The estimated hepatitis C seroprevalence and key population sizes in San Diego in 2018

The Eliminate Hepatitis C San Diego County Initiative was established to provide a roadmap to reduce new HCV infections by 80% and HCV-related deaths by 65% by 2030. An estimate of the burden of HCV infections in San Diego County is necessary to inform planning and evaluation efforts. Our analysis was designed to estimate the HCV burden in San Diego County in 2018.

We synthesized data from the American Community Survey, Centers for Disease Control and Prevention, California Department of Public Health, Public Health Branch of California Correctional Health Care Services, San Diego Blood Bank, and published literature. Burden estimates were stratified by subgroup (people who inject drugs in the community [PWID], men who have sex with men in the community [MSM], general population in the community [stratified by age and sex], and incarcerated individuals). To account for parameter uncertainty, 100,000 parameter sets were sampled from each parameter's uncertainty distribution, and used to calculate the mean and 95% confidence interval estimates of the number of HCV seropositive adults in San Diego in 2018.

We found there were 55,354 (95% CI: 25,411-93,329) adults with a history of HCV infection in San Diego County in 2018, corresponding to an HCV seroprevalence of 2.1% (95% CI: 1.1-3.4%). Over 40% of HCV infections were among the general population aged 55-74 and one-third were among PWID.

Our study found that the largest share of infections was among adults aged 55-74, indicating the importance of surveillance, prevention, testing, and linkages to care in this group to reduce mortality. Further, programs prioritizing PWID for increased HCV testing and linkage to care are important for reducing new HCV infections.