Figure 2. Relationship between age and serum concentration and avidity of measles-reactive IgG in AME patients and controls.

Results are shown for 15 AME patients (top panels) and 13 controls (bottom panels). Results are categorized as being tested before (○) or from day 7 since fever onset (•) because titers increased from day 7. Results for tests done before and after day 7 since fever for two AME patients are joined by a line. One patient tested more than 19 days after fever onset is indicated (*). Sera that were tested after administration of IVIG are also indicated (#). Vertical lines differentiate patients born before and after measles vaccine was widely available in Vietnam. Horizontal lines in panel B indicate avidity cut-offs for identifying secondary (upper) and primary (lower) type antibody responses with intermediate levels being indeterminate.