Clinical assessment of a point-of-care assay to determine protective vaccinal antibody titers to canine viral diseases

Abstract

Guidelines recommend that dogs are vaccinated for canine distemper virus (CDV), canine parvovirus (CPV), and canine adenovirus (CAV) every 3 years. Alternatively, their antibody titers are measured and vaccines given when titers fall below a protective threshold. In this study, a point-of-care (POC) assay was compared to hemagglutination inhibition (for CPV) and virus neutralization (for CAV and CDV) assays to predict the need for revaccination Ninety-two dogs presented for vaccination were enrolled. The POC assay indicated protective titers against CDV in 79/80, CPV in 89/90, and CAV in 91/91 dogs with reference standard antibody measurements that were over a protective threshold. The sensitivity of the POC assay for to detect protective concentrations of CDV antibodies was 99% (95% confidence interval [CI 95%], 93.3–99.9%). Ten dogs were falsely considered protected against CDV by the POC assay with a specificity of 17% (CI 95%, 3.0–44.8%). The sensitivity of the POC assay for protective concentrations of CPV titers was 99% (CI 95%, 93.9–99.9%). The sensitivity of the POC assay to detect protective concentrations of CAV antibodies was 100% (CI 95%, 95.9–100%). Only classifying high-positive CDV and CPV titers on the POC assay as protective improved assay specificity to 100%, but sensitivity decreased to 51% and 76% respectively. This POC assay had a high sensitivity for the detection of protective antibody titers; however, some dogs were falsely categorized as protected, especially for CDV.