“…Regarding the ascertainment of ZIKV infection, 13 studies tested their cases for both PCR and IgM, [4, 14-18, 21, 25, 26, 28, 30, 31, 33] five only for PCR, [19,20,22,29,32] and three only for IgM. [23, 24, 27] Based on the CDC ZIKV case definition, more than a half of all GBS cases with this data available had a suspected ZIKV infection (324/570, 57%), which gives a high risk for ascertainment bias within studies and heterogeneity across studies.…”