910. Evaluation of an Enzymatic Immunoassay System for Detection and Differentiation of Rat Hepatitis E Virus Infection in Humans

Abstract Background Previously, hepatitis E in humans was believed to be caused exclusively by species A variants of the Orthohepevirus genus (HEV-A) of the family Hepeviridae. However, we have previously demonstrated that Orthohepevirus species C (HEV-C), also known as rat hepatitis E virus, also causes hepatitis in humans. Due to high sequence divergence between HEV-A and HEV-C, serological tests based on HEV-A are often insensitive for HEV-C diagnosis. Therefore, we developed an enzymatic immunoassay (EIA) system for differentiating HEV-A and HEV-C antibody signatures in patient sera. Methods HEV-A and HEV-C peptide homologs spanning the entire immunogenic E2s region of HEV ORF2 capsid protein were expressed in E. coli. These peptides, HEV-A4 p239 and HEV-C p241, form virus-like particles (figure 1). Both peptides were coated in separate 96-well plates. Sera obtained from patients with RT-PCR confirmed acute HEV-A infection (n = 54), HEV-C infection (n = 15), and uninfected HEV seronegative controls (n = 126) were tested in parallel in HEV-A4 p239 and HEV-C p241 EIAs for respective IgG antibodies. Sample optical densities (ODs) were divided by mean OD + 3SD of the seronegative controls to generate signal/noise (S/N) ratios. S/Ns marking positivity in either assay were determined by ROC analysis. An algorithm for assay interpretation was developed (table 1) and the performance of this algorithm was measured against the RT-PCR gold standard. HEV-A4 p239 and HEV-C1 p241 virus like particles Transmission electron microscopy images of the two peptides used in this study Diagnostic testing algorithm interpretation Interpretation of results of testing using parallel enzymatic immunoassays Results Using cutoffs determined by ROC analysis (figure 2), HEV-A4 p239 and HEV-C p241 EIAs detected species-specific antibody responses well (sensitivity: 92.6% and 80% respectively) and were specific (92.9% and 98.3% respectively). The DC was 100% congruent with HEV-C RT-PCR and 88.9% congruent with HEV-A RT-PCR in RT-PCR positive samples. Incorporating all three cutoffs into the algorithm, we derived a 3×3 confusion matrix of RT-PCR sample assignation vs EIA algorithm classification (table 2). The Cohen’s κ value was 0.883 indicating excellent inter-rater reliability. ROC analysis for determining S/N cutoffs Curve for A/A represents analysis for HEV-A4 p239 EIA. Curve for C/¬C represents analysis for HEV-C p241 EIA. Curve for r(C/A) represents analysis for the differentiating ratio. 3×3 confusion matrix comparing sample assignations by RT-PCR vs. EIA algorithm Conclusion A parallel EIA system accurately differentiated HEV-A and HEV-C serological signatures in acute patient sera. This method can now be applied to seroprevalence studies to determine seroprevalence of rat hepatitis E in human populations. Disclosures Siddharth Sridhar, FRCPath, Abbott (Other Financial or Material Support, Speaker’s honoraria)

studied or reported. We performed a pilot treatment study in a young cohort of PWIDS to evaluate cure rates of HCV in this population.
Methods. Young, active PWIDS using < 6months earlier, < 35 yoa were identified. Treatment for HCV with glecaprevir/pibrentasvir (G/P) and concurrent treatment for opiate use disorder with XR Naletrexone (XR-NTX) was provided. Two patients chose methadone. Patients were followed up to 12 months after enrollment. Patients were evaluated for adherence, side effects, alanine aminotransferase (ALT) levels, urine drug screens (UDS) and opioid craving scores using a visual analog scale (VAS) while on XR-NTX to assess management of their addiction. Rates of treatment completion, SVR 4 & 12 were determined.
Results. 30 patients were recruited: 18 were women. Average age was 28 with a range of 23-35. Recent injection drug use was common with 22 (73%) having injected within the 30 days and all having injected within 3 months of recruitment. The average ALT on enrollment was 106. Genotypes were 1 (15), 3a (11), and unknown (4). Of the 30 patients, 15 failed to come for the required 2 visits prior to starting G/P. Lost to follow up occurred due to relapse of addiction (9), overdose death (1), lost communication and suspected relapse (4). 15 began and completed G/P. 15 were cured of their HCV infection. 17 patients receive one or more doses of XR-NTX. On average patients were on XR-NTX for 4.8 months. Sobriety was measured for patients on XR-NTX using Opiate Craving Scores using the Visual Analogue Scale (VAS) and UDS ( Figure  1) demonstrating excellent control of craving and significant declines positive UDS. Toxicities were uncommon with no treatment limiting adverse events. Adverse effects of XR-NTX included mild injection site irritation. No ALT abnormalities were noted.

Conclusion.
Young active PWIDS can successfully be cured of HCV. Their addiction can be concurrently managed with XR-NXT. Our findings suggest it is safe to treatment active users with active HCV with XR-NXT improving elimination goals. Background. Previously, hepatitis E in humans was believed to be caused exclusively by species A variants of the Orthohepevirus genus (HEV-A) of the family Hepeviridae. However, we have previously demonstrated that Orthohepevirus species C (HEV-C), also known as rat hepatitis E virus, also causes hepatitis in humans. Due to high sequence divergence between HEV-A and HEV-C, serological tests based on HEV-A are often insensitive for HEV-C diagnosis. Therefore, we developed an enzymatic immunoassay (EIA) system for differentiating HEV-A and HEV-C antibody signatures in patient sera.
Methods. HEV-A and HEV-C peptide homologs spanning the entire immunogenic E2s region of HEV ORF2 capsid protein were expressed in E. coli. These peptides, HEV-A4 p239 and HEV-C p241, form virus-like particles (figure 1). Both peptides were coated in separate 96-well plates. Sera obtained from patients with RT-PCR confirmed acute HEV-A infection (n = 54), HEV-C infection (n = 15), and uninfected HEV seronegative controls (n = 126) were tested in parallel in HEV-A4 p239 and HEV-C p241 EIAs for respective IgG antibodies. Sample optical densities (ODs) were divided by mean OD + 3SD of the seronegative controls to generate signal/noise (S/N) ratios. S/Ns marking positivity in either assay were determined by ROC analysis. An algorithm for assay interpretation was developed (table 1) and the performance of this algorithm was measured against the RT-PCR gold standard.
HEV-A4 p239 and HEV-C1 p241 virus like particles Transmission electron microscopy images of the two peptides used in this study Diagnostic testing algorithm interpretation Interpretation of results of testing using parallel enzymatic immunoassays Results. Using cutoffs determined by ROC analysis (figure 2), HEV-A4 p239 and HEV-C p241 EIAs detected species-specific antibody responses well (sensitivity: 92.6% and 80% respectively) and were specific (92.9% and 98.3% respectively). The DC was 100% congruent with HEV-C RT-PCR and 88.9% congruent with HEV-A RT-PCR in RT-PCR positive samples. Incorporating all three cutoffs into the algorithm, we derived a 3×3 confusion matrix of RT-PCR sample assignation vs EIA algorithm classification (table 2). The Cohen's κ value was 0.883 indicating excellent inter-rater reliability.
ROC analysis for determining S/N cutoffs Curve for A/A represents analysis for HEV-A4 p239 EIA. Curve for C/¬C represents analysis for HEV-C p241 EIA. Curve for r(C/A) represents analysis for the differentiating ratio.
3×3 confusion matrix comparing sample assignations by RT-PCR vs. EIA algorithm Conclusion. A parallel EIA system accurately differentiated HEV-A and HEV-C serological signatures in acute patient sera. This method can now be applied to seroprevalence studies to determine seroprevalence of rat hepatitis E in human populations.

Rapid Hepatitis C Treatment Initiation in Young People Who Inject Drugs: Final Results from the HCV-Seek, Test and Rapid Treatment (HCV-ST&RT) Randomized Pilot Clinical Trial
Benjamin Eckhardt, MD, MS 1 ; Shashi Kapadia, MD 2 ; Melinda Smith, MA 2 ; Yesenia Aponte-Melendez, PhD 3 ; Chunki Fong, MS 3 ; La Davis, n/a 3 ; Pedro Mateu-Gelabert, PhD 3 ; Kristen Marks, MD 2 ; Kristen Marks, MD 2 ; 1 NYU School of Medicine/Bellevue Hospital, New York, NY; 2 Weill Cornell Medicine, New York, NY; 3 CUNY School of Public Health, New York, New York Session: P-52. Hepatitis Background. Young people who inject drugs (PWID) have higher HCV incidence and lower treatment initiation rates compared to their older peers. Novel, simplified care models need to be developed to engage, treat and cure hard to reach patient populations, such as young PWID.
Methods. We present final data from the randomized pilot clinical trial HCV-Seek Test & Rapid Treatment (HCV-ST&RT) for curing HCV in young PWID. Eligible participants were 18-29 years of age, HCV Ab+, treatment naïve, and had injected drugs in the past 30 days. Participants were randomized 1:1 to the Rapid Treatment or Usual Care arm. Participants randomized to Rapid Treatment received a same-day medical evaluation, confirmatory and baseline lab testing, and 7-day starter pack of sofosbuvir/velpatasvir. Participants in Usual Care received same-day HCV confirmatory testing and, if positive, facilitated referral to local providers. The primary endpoint was sustained virologic response (SVR12) in RNA+ participant within 12 months of enrollment.
Results. Among 47 eligible participants, 38 were enrolled and randomized. 14/18 in the Rapid Treatment arm and 11/20 in the Usual Care arm were confirmed HCV RNA+ and included in the intention-to-treat analysis. Demographics of the RNA+ participants were similar in the two arms with a mean age of 26 years; 24% women; 36% Hispanic and 4% non-Hispanic black. At baseline 24% were homeless, 52% received medication for opioid use disorder in the prior 90 days, and participants injected a median of 20 of the last 30 days. In the intention-to-treat analysis, 9/14 (64%) of the Rapid Treatment arm and 2/11 (18%) of the Usual Care arm had confirmed SVR12 (p=0.042). Of the 5 participants in the Rapid Treatment arm who did not achieve SVR12, 1 had treatment failure, 1 never started DAA therapy, 1 had an on-treatment response with pending SVR12 confirmation, and 2 were lost to follow-up.
Conclusion. Among young HCV RNA+ PWID, significantly higher rates of cure were achieved using the Rapid Treatment model with same day, low-threshold, simplified HCV care compared to facilitated referral. Meeting young PWID where they're at and initiating HCV treatment 'in the moment' without the need for repeat visits appears to be a promising strategy for treating this hard to reach population.
Disclosures Background. It is estimated that nearly 80,000 people with hepatitis C are living in Louisiana, many with Medicaid coverage. Previously, only Medicaid patients free from drugs and alcohol with a fibrosis score of F3 or F4 were eligible for treatment, resulting in few patients receiving treatment. Beginning in July 2019, generic sofosbuvir/velpatasvir was made available through the Medicaid program in a subscription model, allowing unlimited hepatitis C treatment in Louisiana's Medicaid program for 5 years at a set price to the program. This has dramatically expanded access to Hepatitis C treatment for people with Medicaid in Louisiana.
Methods. Patients with Hepatitis C seen in the Infectious Diseases Center at University Medical Center in New Orleans, in 2020 by the 5 main hepatitis C providers were included. Demographics and laboratory data were collected to determine outcomes.
Results. Most patients with a hepatitis C (HCV) viral load and insurance data had Medicaid (80%, N=275). Twenty-two (8%) were HIV co-infected. Most were men (75%) and African-American (77%). Among the mono-infected patients with Medicaid and an HCV viral load, 216 (85%) had an undetectable viral load by the beginning of June 2021. Of the remaining 37 patients, 30 patients were prescribed treatment; but did not take it (n=4), didn't follow-up (n=23), or followed-up but never got labs (n=3). One was treated but had a treatment failure (n=1). Six of the 37 were not prescribed medications due to a short life expectancy or significant drug interactions. The percentage of patients with an undetectable viral load was similar by gender and race, however younger age groups had lower viral suppression. In those aged less than 35, only 47% had an undetectable viral load and among those aged 36 to 44, it was 66%. Using the previous criteria of requiring a fibrosis score of F3 or F4, only 20% (n=44) would have been eligible for medicine to treat hepatitis C.