Combating Related Epidemics in HCV (CREST)

Inclusion Criteria:

1. Can provide written informed consent or assent
2. Minimum of 16 years of age
3. Willing to undergo HIV, HCV, HBV testing
4. Willing to undergo treatment for HCV and complete study activities

Exclusion Criteria:

1. History of HCV treatment for current infection
2. Known preexisting (evidence or history of) decompensated liver disease based on: medical diagnosis through medical record, reporting by the participant, or clinical evidence per the site PI
3. Contraindication for treatment with sofosbuvir/velpatasvir due to allergy or drug-drug interaction including use of any prohibited concomitant medications within 28 days prior to study entry.
4. History of clinically significant illness or any other major medical disorder that may interfere with participant treatment, assessment, or compliance with study requirements as determined by the site PI
5. Ongoing need for use of daily proton pump inhibitor (PPI) at doses ≥40 mg of omeprazole (or equivalent). NOTE: PPI can be discontinued or dose reduced to 20 mg/day of omeprazole (or equivalent) at time of study entry.

Retreatment Inclusion Criteria:

1. Completion of sofosbuvir/velpatasvir treatment regimen as enrolled participant in CREST and willingness to receive retreatment. FIB-4 & CTP score available within 90-days of retreatment initiation.
2. Meeting any of the below criteria during post-cessation treatment follow-up. Relapse, defined as HCV RNA <LLOQ/D (TD or TND) during and/or at end of treatment followed by HCV RNA >LLOQ/D or target detected based on qualitative POC test at any time point from end of treatment to 12 weeks after end of treatment OR Re-infection, defined as meeting the primary outcome criteria for SVR4+ followed by HCV RNA >LLOQ/D or target detected based on qualitative POC test at any time point beyond meeting SVR4+ OR Post-treatment virologic failure, defined as HCV RNA >LLOQ/D at any point after end of treatment (after week 24 visit) or during follow-up, not otherwise meeting definition of relapse or re-infection

Retreatment Exclusion Criteria:

1. Known preexisting (evidence or history of) decompensated liver disease based on: medical diagnosis through medical record, reporting by the participant, clinical evidence per the site PI, or by CTP score ≥7.
2. Pregnant or breast feeding at time of retreatment with sofosbuvir/velpatasvir/voxilaprevir.
3. Contraindication for treatment with sofosbuvir/velpatasvir (reinfection) or sofosbuvir/velpatasvir/voxilaprevir (relapse or virologic failure) due to FDA package insert, allergy, or drug-drug interaction including use of any prohibited concomitant medications within 28 days prior to study entry.
4. History of clinically significant illness or any other major medical disorder that may interfere with participant treatment, assessment, or compliance with study requirements as determined by the site PI
5. Ongoing need for use of daily proton pump inhibitor (PPI) at doses ≥40 mg of omeprazole (or equivalent.). NOTE: PPI can be discontinued or dose reduced to 20 mg/day of omeprazole (or equivalent) at time of study entry.