Background: The plaque reduction neutralization test (PRNT) is currently the best and most widely accepted approach to measuring virus-neutralizing and protective antibodies to dengue virus, and in assessing the immunogenicity of a dengue vaccine. However, the correlation between presence of dengue-neutralizing antibody and protection from infection is not absolute.
Findings: In a cohort study in Ratchaburi Province, Thailand, 48 subjects with serologically confirmed symptomatic dengue infection were tested for pre-existing dengue neutralizing antibody using PRNT. Nine subjects had quite high pre-existing PRNT50 titers (titer >90) to subsequent infecting dengue serotypes, but still had symptomatic infections.
Conclusion: This report provides evidence that PRNT may not be a good test for predicting protection against subsequent dengue infection.