IGHG3 and Zika virus infectious disease: Cases were defined as having robust evidence of maternal ZIKV infection if they had a positive nucleic acid amplification test, seroconversion, or at least two positive serologic tests in pregnancy of if they had one positive serologic tests (i.e., IgM or IgG3) in pregnancy paired with a non-negative PRNT50 within six months post-pregnancy (Fig 4).