AQP4 and COVID-19: Interestingly, genetic liability to COVID-19 susceptibility was nominally associated with AQP4+NMOSD by implementing the IVW approach (OR = 4.958, 95% CI: 1.322-18.585, P = 0.018; Figure 2), consistent with MR Egger, weighted median and weighted mode (Supplementary Figures S1-3).