Duration of serologic response to five viral antigens in dogs

Abstract

Objective-To determine whether vaccinated dogs either remained seropositive or responded serologically to revaccination for 5 key viral antigens after extended periods since their last vaccination. Design-Serologic survey. Animals-322 healthy client-owned dogs. Procedure-Dogs were ≥ 2 years old and vaccinated against canine distemper virus (CDV), canine adenovirus-1 (CAV-1), canine adenovirus-2 (CAV-2), canine parainfluenza virus (CPIV), and canine parvovirus (CPV). On day 0, dogs were revaccinated with a vaccine from the same vaccine line as they had historically received. Antibody titers were measured in sera collected at day 0 (prevaccination titer) and 5 to 7 days later (postvaccination titer). Dogs were considered to have responded serologically if they had a day-0 serum neutralization titer to CDV ≥ 1:32; a serum neutralization titer to CAV-1, CAV-2, or CPIV ≥ 1:16; a hemagglutination inhibition titer to CPV ≥ 1:80; or a ≥ 4-fold increase in antibody titer after revaccination. Results-The percentage of dogs that had titers at or greater than the threshold values or responded to revaccination with a ≥ 4-fold increase in titer was 98.1% for CDV, 98.4% for CAV-1, 99.0% for CAV-2, 100% for CPIV, and 98.1% for CPV. Conclusions and Clinical Relevance-In most dogs, vaccination induced a response that lasted up to and beyond 48 months for all 5 antigens. Although not equivalent to challenge-of-immunity studies as a demonstration of efficacy, results suggest that revaccination with the same vaccine provides adequate protection even when given less frequently than the traditional 1-year interval. The study provides valuable information for clinicians to help determine appropriate revaccination intervals.