Theme: Epidemiology & Public Health Research Year: 2022
Background:
In 2017, San Francisco’s HCV elimination initiative generated an estimate of city-wide HCV prevalence in
2015. Using additional data and improved methods, we aimed to update the 2015 estimate to 2019 and
more accurately estimate the number of people with untreated, active HCV infection overall and in key
subgroups, including people who inject drugs (PWID).
Methods:
Our estimates are based on triangulation of data from blood banks, cross-sectional and longitudinal
observational studies, and published literature. While for 2015 we could only gather an aggregate
number of known treatment starts with direct-acting antivirals (to subtract from active HCV infections
citywide as “presumed cured”), for the 2019 estimate we were able to pool estimates of treatment rates
for each subgroup, allowing for a substantially refined estimate of remaining untreated infections.
Results:
The total number of San Francisco residents estimated to have anti-HCV antibodies in 2019 was 22,585
(plausible range, PR:12,014–44,152), with a citywide seroprevalence of 2.6% (PR:1.4%–5.0%) – similar to
the 2015 estimate of 21,758 (PR:10,274–42,067). Of those, approximately 11,582 (PR:4,864–35,094) had
untreated, active HCV infection, representing 51.3% (PR:40.5%–79.5%) of all people with anti-HCV
antibodies, and 1.3% (PR:0.6%–4.0%) of all San Franciscans. PWID are 2.8% of the total San Francisco
population, yet 73.1% of those with anti-HCV antibodies and 90.4% of those with untreated, active HCV
infection.
Conclusion:
While plausible ranges are wide, these findings indicate that the overall number of people with anti-HCV
antibodies may have increased slightly, and the number of people with active HCV infection may have
decreased slightly since 2015. This estimate improves upon the 2015 calculations by directly estimating
the impact of curative treatment, and will allow for more comparable results in subsequent estimate
updates, tracking elimination progress.
Disclosure of Interest Statement:
Drs Facente and Grebe have received consulting fees from Gilead Sciences for unrelated work. Dr Morris
and Ms Hecht have received grant funding from Gilead Sciences for unrelated work. No pharmaceutical
grants were received in the development of this work, though Gilead Foundation and AbbVie Foundation
have provided grant support to End Hep C SF for other efforts.