Antibody avidity following secondary dengue virus type 2 infection across a range of disease severity

•We studied antibody avidity kinetics relative to disease severity post-secondary DENV2 infection.•Avidity increased between acute and convalescence and stabilized from 3 to 18 months post-illness.•Sera from DHF/DSS cases had lower avidity at 18 months post-illness than DF cases.•A faster rate of decay in avidity was observed in DHF/DSS compared to DF cases.•Severe dengue was associated with lower antibody avidity at later times post-illness.