Rapid diagnostic HCV antibody assays

Adenoviruses vectored hepatitis C virus vaccine cocktails induce broadly specific immune responses against multi-genotypic HCV in mice

BACKGROUND

Hepatitis C virus (HCV) vaccines are an urgent need to prevent hepatitis C and its further progression of hepatocellular carcinoma. Since the promising T cell based chimpanzee adenovirus and modified vaccinia virus Ankara vectorial HCV vaccines were failed in clinical phase II trial, the vaccine designs to improve protection efficacy in combination of cellular and humoral immunity have been hypothesized against multi-genotypic HCV.

METHODS

Eight HCV vaccine strains were constructed with two novel adenovirus vectors (Sad23L and Ad49L) encoding E1E2 or NS3-5B proteins of HCV genotype (Gt) 1b and 6a isolates, covering 80 % HCV strains prevalent in south China and south-east Asia. Eight HCV vaccine strains were grouped into Sad23L-based vaccine cocktail-1 and Ad49L-based vaccine cocktail-2 for vaccinating mice, respectively.

RESULTS

The immunogenicity of a single dose of 107-1010 PFU HCV individual vaccines was evaluated in mice, showing weak specific antibody to E1 and E2 protein but a dose-dependent T cell response to E1E2/NS3-5B peptides, which could be significantly enhanced by boosting with an alternative vector vaccine carrying homologous antigen. Prime-boost vaccinations with vaccine cocktail-1 and cocktail-2 induced significantly higher cross-reactive antibody and stronger T cell responses to HCV Gt-1b/6a. The high frequency of intrasplenic and intrahepatic NS31629-1637 CD8+ T cell responses were identified, in which the high proportion of TRM and TEM cells might play an important role against HCV infection in liver.

CONCLUSIONS

Prime-boost regimens with HCV vaccine cocktails elicited the broad cross-reactive antibody and robust T cell responses against multi-genotypic HCV in mice.

Hepatitis C outreach project and cross-sectional epidemiology in high-risk populations in Trondheim, Norway

BACKGROUND

Hepatitis C is highly prevalent among people who use drugs (PWUD), and the hepatitis C virus (HCV) epidemic is less characterised in Norway. The aims of the study were to assess the prevalence and treatment willingness in high-risk populations by reaching out to frequently visited sites for high-risk populations.

METHODS

Individuals from high-risk populations were included from September 2015 to March 2017. Two dedicated study nurses frequently visited the local opioid substitution clinic, outpatient clinics, PWUD day centres, local prison, and refugee centre in Trondheim, Norway. Demographic data, risk behaviour, and clinical symptoms were obtained by study questionnaire. Subjects with anti-HCV+ rapid test were subsequently tested for HCV RNA and genotyped. Viraemic patients were offered referral for HCV treatment evaluation.

RESULTS

A total of 381 participants were included in the study: 52 immigrants, 62 prisoners, and 267 PWUD. The anti-HCV prevalence rates were 0% (n = 0) in immigrants, 40% (n = 25) in prisoners, and 61% (n = 164) in PWUD, with 24% (n = 15) of prisoners and 42% (n = 108) of PWUD being viraemic. Of those qualifying for treatment (n = 31), 30 wished to be evaluated.

CONCLUSION

This study showed high HCV prevalence in prisoners and PWUD and that infected high-risk patients were interested in treatment evaluation.

Pharmacy-Based Infectious Disease Management Programs Incorporating CLIA-Waived Point-of-Care Tests

There are roughly 48,000 deaths caused by influenza annually and an estimated 200,000 people who have undiagnosed human immunodeficiency virus (HIV). These are examples of acute and chronic illnesses that can be identified by employing a CLIA-waived test. Pharmacies across the country have been incorporating CLIA-waived point-of-care tests (POCT) into disease screening and management programs offered in the pharmacy. The rationale behind these programs is discussed. Additionally, a summary of clinical data for some of these programs in the infectious disease arena is provided. Finally, we discuss the future potential for CLIA-waived POCT-based programs in community pharmacies.

Developments in the HCV Screening Technologies Based on the Detection of Antigens and Antibodies

Hepatitis C virus (HCV) accounts for 15%-20% of cases of acute infection, and chronic HCV infection is developed in about 50%-80% of HCV patients. Unfortunately, due to the lack of proper medical care, difficulty in screening for HCV infection, and lack of awareness resulted in chronic HCV infection in 71 million people on a global scale, and about 399,000 deaths in 2016. It is crucial to recognize that the effective use of antiviral medicines can cure more than 95% of HCV infected people. The Global Health Sector Strategy (GHSS) aim is to reduce the new HCV infections and the HCV associated mortality by 90% and 65%, respectively. Therefore, the methods that are simple, yet powerful enough to detect HCV infections with high sensitivity, specificity, and a shorter window period are crucial to restrain the global burden of HCV healthcare. This article focuses on the technologies used for the detection of HCV in clinical specimens.

Development of a Rapid Automated Fluorescent Lateral Flow Immunoassay to Detect Hepatitis B Surface Antigen (HBsAg), Antibody to HBsAg, and Antibody to Hepatitis C

Background

Accurate, rapid, and cost-effective screening tests for hepatitis B virus (HBV) and hepatitis C virus (HCV) infection may be useful in laboratories that cannot afford automated chemiluminescent immunoassays (CLIAs). We evaluated the diagnostic performance of a novel rapid automated fluorescent lateral flow immunoassay (LFIA).

Methods

A fluorescent LFIA using a small bench-top fluorescence reader, Automated Fluorescent Immunoassay System (AFIAS; Boditech Med Inc., Chuncheon, Korea), was developed for qualitative detection of hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), and antibody to HCV (anti-HCV) within 20 minutes. We compared the diagnostic performance of AFIAS with that of automated CLIAs—Elecsys (Roche Diagnostics GmbH, Penzberg, Germany) and ARCHITECT (Abbott Laboratories, Abbott Park, IL, USA)—using 20 seroconversion panels and 3,500 clinical serum samples.

Results

Evaluation with the seroconversion panels demonstrated that AFIAS had adequate sensitivity for HBsAg and anti-HCV detection. From the clinical samples, AFIAS sensitivity and specificity were 99.8% and 99.3% for the HBsAg test, 100.0% and 100.0% for the anti-HBs test, and 98.8% and 99.1% for the anti-HCV test, respectively. Its agreement rates with the Elecsys HBsAg, anti-HBs, and anti-HCV detection assays were 99.4%, 100.0%, and 99.0%, respectively. AFIAS detected all samples with HBsAg genotypes A-F and H and anti-HCV genotypes 1, 1a, 1b, 2a, 2b, 4, and 6. Cross-reactivity with other infections was not observed.

Conclusions

The AFIAS HBsAg, anti-HBs, and anti-HCV tests demonstrated diagnostic performance equivalent to current automated CLIAs. AFIAS could be used for a large-scale HBV or HCV screening in low-resource laboratories or low-to middle-income areas.

Hepatitis virus (HCV) diagnosis and access to treatment in a UK cohort

Background

As direct acting antiviral (DAA) therapy is progressively rolled out for patients with hepatitis C virus (HCV) infection, careful scrutiny of HCV epidemiology, diagnostic testing, and access to care is crucial to underpin improvements in delivery of treatment, with the ultimate goal of elimination.

Methods

We retrospectively studied microbiology records from a large UK teaching hospital in order to compare the performance of HCV screening and diagnostic tests (antibody, antigen and HCV RNA detection). Having described a local cohort of adults with active HCV infection, we investigated the proportion who attended hospital appointments, were prescribed direct acting antiviral (DAA) therapy, and cleared HCV RNA following treatment.

Results

Over a total time period of 33 months between 2013 and 2016, we tested 38,509 individuals for HCV infection and confirmed a new diagnosis of active HCV infection (HCV-Ag + and/or HCV RNA+) in 353 (positive rate 0.9%). Our in-house HCV-Ab screening test had a positive predictive value of 87% compared to repeat HCV-Ab testing in a reference laboratory, highlighting the potential for false positives to arise using this test. HCV-Ag had 100% positive predictive value compared to detection of HCV RNA. There was a strong correlation between quantitative HCV-Ag and HCV RNA viral load (p < 0.0001). Among the cases of infection, genotype-1 and genotype-3 predominated, the median age was 37 years, 84% were male, and 36% were in prison. Hepatology review was provided in 39%, and 22% received treatment. Among those who received DAA therapy with 12 weeks of follow-up, 93% achieved a sustained virologic response (SVR₁₂).

Conclusions

HCV-Ag performs well as a diagnostic test compared to PCR for HCV RNA. Active HCV infection is over-represented among men and in the prison population. DAA therapy is successful in those who receive it, but a minority of patients with a diagnosis of HCV infection access clinical care. Enhanced efforts are required to provide linkage to clinical care within high risk populations.

Potential for Pharmacy-Public Health Collaborations Using Pharmacy-Based Point-of-Care Testing Services for Infectious Diseases

CONTEXT

Health care professionals must continually identify collaborative ways to combat antibiotic resistance while improving community health and health care delivery. Clinical Laboratory Improvement Amendments of 1988 (CLIA)-waived point-of-care (POC) testing (POCT) services for infectious disease conducted in community pharmacies provide a means for pharmacists to collaborate with prescribers and/or public health officials combating antibiotic resistance while improving community health and health care delivery.

OBJECTIVE

To provide a comprehensive literature review that explores the potential for pharmacists to collaborate with public health professionals and prescribers using pharmacy-based CLIA-waived POCT services for infectious diseases.

DESIGN

Comprehensive literature review.

SETTING

PubMed and Google Scholar were searched for manuscripts and meeting abstracts for the following key words: infectious disease, community pharmacy, rapid diagnostic tests, rapid assay, and POC tests.

INTERVENTION

All relevant manuscripts and meeting abstracts utilizing POCT in community pharmacies for infectious disease were reviewed.

OUTCOME MEASURE

Information regarding the most contemporary evidence regarding CLIA-waived POC infectious diseases tests for infectious diseases and their use in community pharmacies was synthesized to highlight and identify opportunities to develop future collaborations using community pharmacy-based models for such services.

RESULTS

Evidence demonstrates that pharmacists in collaboration with other health care professionals can leverage their knowledge and accessibility to provide CLIA-waived POCT services for infectious diseases. Testing for influenza may augment health departments' surveillance efforts, help promote rationale antiviral use, and avoid unnecessary antimicrobial therapy. Services for human immunodeficiency virus infection raise infection status awareness, increase access to health care, and facilitate linkage to appropriate care. Testing for group A streptococcal pharyngitis may curb inappropriate outpatient antibiotic prescribing. However, variance in pharmacy practice statues and the application of CLIA across states stifle collaboration.

CONCLUSION

CLIA-waived POCT services for infectious diseases are a means for pharmacists, public health professionals, and prescribers to collaboratively combat antibiotic resistance and improve community health.

A pilot study of rapid hepatitis C virus testing in the Rhode Island Department of Corrections

BACKGROUND

The correctional population bears a heavy burden of hepatitis C virus (HCV) infection necessitating expansion of HCV testing and treatment opportunities. Rapid HCV testing provides point-of-care antibody results and may be ideal for correctional facilities, particularly jails, where persons are often incarcerated for short periods of time, yet feasibility has not been established.

METHODS

We conducted a pilot study of a rapid HCV testing algorithm among short-term inmates with unknown HCV status. Participants completed a questionnaire, viewed an informational video and underwent rapid HCV testing and confirmatory testing, when indicated. Persons with chronic infection were referred to community care after release. Baseline characteristics, risk behaviors, test results and linkage were examined by descriptive analyses.

RESULTS

Two hundred and fifty-two inmates were enrolled and 249 completed all study activities. Twenty-five participants (10%) had reactive rapid tests and 23 (92%) completed confirmatory testing. 15/23 (65%) had detectable HCV RNA, but only 4 linked to care after release. Persons with reactive HCV tests were more likely to be White (P = 0.01) and to have ever injected (P < 0.0001) and/or recently injected (P < 0.0001) drugs.

CONCLUSIONS

Rapid HCV testing within jails is feasible, identifies previously unrecognized cases of HCV infection, and implementation should be considered. Low rates of linkage to care after release remain a barrier to care.

Diagnostic accuracy of point-of-care tests for hepatitis C virus infection: a systematic review and meta-analysis

Background

Point-of-care tests provide a plausible diagnostic strategy for hepatitis C infection in economically impoverished areas. However, their utility depends upon the overall performance of individual tests.

Methods

A literature search was conducted using the metasearch engine Mettā, a query interface for retrieving articles from five leading medical databases. Studies were included if they employed point-of-care tests to detect antibodies of hepatitis C virus and compared the results with reference tests. Two reviewers performed a quality assessment of the studies and extracted data for estimating test accuracy.

Findings

Thirty studies that had evaluated 30 tests fulfilled the inclusion criteria. The overall pooled sensitivity, specificity, positive likelihood-ratio, negative likelihood-ratio and diagnostic odds ratio for all tests were 97.4% (95% CI: 95.9–98.4), 99.5% (99.2–99.7), 80.17 (55.35–116.14), 0.03 (0.02–0.04), and 3032.85 (1595.86–5763.78), respectively. This suggested a high pooled accuracy for all studies. We found substantial heterogeneity between studies, but none of the subgroups investigated could account for the heterogeneity. Genotype diversity of HCV had no or minimal influence on test performance. Of the seven tests evaluated in the meta-regression model, OraQuick had the highest test sensitivity and specificity and showed better performance than a third generation enzyme immunoassay in seroconversion panels. The next highest test sensitivities and specificities were from TriDot and SDBioline, followed by Genedia and Chembio. The Spot and Multiplo tests produced poor test sensitivities but high test specificities. Nine of the remaining 23 tests produced poor test sensitivities and specificities and/or showed poor performances in seroconversion panels, while 14 tests had high test performances with diagnostic odds ratios ranging from 590.70 to 28822.20.

Conclusions

Performances varied widely among individual point-of-care tests for diagnosis of hepatitis C virus infection. Physicians should consider this while using specific tests in clinical practice.