Figure 2. Zika virus and CHIKV antibody dynamics among samples from patients in Brazil, 2016. A) Percentage seroconversion for markers of acute infection with Zika virus and CHIKV (IgM NS1–based Zika virus ELISA, IgM envelope-based Zika virus ELISA, IgM μ-capture Zika virus ELISA, IgA NS1-based Zika virus ELISA, IgM CHIKV ELISA) at any time point. B) Median ELISA ratios for Zika virus and CHIKV IgM and IgA over time. C) Percentage seroconversion for markers of convalescence after Zika virus and CHIKV infection (IgG NS1-based Zika virus ELISA and IgG envelope-based Zika virus ELISA, Zika virus PRNT50, IgG CHIKV ELISA) at any time point. D) Median ELISA ratios for Zika virus and CHIKV IgG over time. Numbers of specimens per time point are shown in Figure 1. Dashed lines indicate signal-to-cutoff ratios of >1.1 considered positive for all ELISAs except μ-capture ELISA, for which the dashed line indicates a signal-to-cutoff ratio of >10, considered positive by the manufacturer. See Appendix Figure 5 for the percentage de novo seroconversion of Zika virus and CHIKV in different assays per time point. CHIKV, chikungunya virus; dpo, days post–symptom onset; E, envelope; NS, nonstructural protein; PRNT, plaque reduction neutralization test.