Anti-Dengue Virus Antibody Avidity Correlates With Protection Against Symptomatic Dengue Virus Infection.

Antibody avidity is indicative of antibody affinity maturation following virus infection or vaccination. To determine correlation between preexisting anti-dengue virus (DENV) antibody avidity and secondary DENV exposure outcomes, we assessed anti-DENV antibody avidity, represented as avidity index (antibody response/dissociation rate) in sera of Nicaraguan Pediatric Dengue Cohort Study participants prior to symptomatic or inapparent secondary DENV infections. The avidity index was significantly higher in participants who subsequently developed inapparent versus symptomatic infections. Risk factor analysis suggested that odds of inapparent DENV infection increase as avidity index increases. Antibody avidity index is an important parameter for characterizing protective DENV immune responses.