Use of Hepatitis C Virus (HCV) Immunoglobulin G Antibody Avidity as a Biomarker to Estimate the Population-Level Incidence of HCV Infection

Eshan U. Patel, Andrea Cox, Shruti Hemendra Mehta, Denali Boon, Caroline E. Mullis, Jacquie Astemborski, William Osburn, Jeffrey Quinn, Andrew Redd, Gregory D Kirk, David L Thomas, Thomas C Quinn, Oliver B. Laeyendecker

Research output: Contribution to journalArticle


Background. Sensitive methods are needed to estimate the population-level incidence of hepatitis C virus (HCV) infection. Methods. We developed an HCV immunoglobulin G (IgG) antibody avidity assay by modifying the Ortho 3.0 HCV enzyme-linked immunoassay and tested 997 serum or plasma samples from 568 people who inject drugs enrolled in prospective cohort studies. Avidity-based testing algorithms were evaluated by their (1) mean duration of recent infection (MDRI), defined as the average time an individual is identified as having been recently infected, according to a given algorithm; (2) false-recent rate, defined as the proportion of samples collected >2 years after HCV seroconversion that were misclassified as recent; (3) sample sizes needed to estimate incidence; and (4) power to detect a reduction in incidence between serial cross-sectional surveys. Results. A multiassay algorithm (defined as an avidity index of <30%, followed by HCV viremia detection) had an MDRI of 147 days (95% confidence interval [CI], 125-195 days), and the false-recent rates were 0.7% (95% CI,. 2%-1.8%) and 7.6% (95% CI, 4.2%-12.3%) among human immunodeficiency virus (HIV)-negative and HIV-positive persons, respectively. In various simulated high-risk populations, this algorithm required <1000 individuals to estimate incidence (relative standard error, 30%) and had >80% power to detect a 50% reduction in incidence. Conclusions. Avidity-based algorithms have the capacity to accurately estimate HCV infection incidence and rapidly assess the impact of public health efforts among high-risk populations. Efforts to optimize this method should be prioritized.

Original languageEnglish (US)
Pages (from-to)344-352
Number of pages9
JournalJournal of Infectious Diseases
Issue number3
StatePublished - Aug 1 2016


  • antibody response
  • HCV
  • HIV
  • incidence testing
  • people who inject drugs
  • recent infection
  • surveillance

ASJC Scopus subject areas

  • Immunology and Allergy
  • Medicine(all)
  • Infectious Diseases

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