Another possible antiviral effect of HCQ is exerted on Zika virus (ZIKV), an RNA virus of the Flaviviridae family transmitted by numerous mosquitoes of the genus Aedes. No clinical studies have been conducted yet, but an in vivo study has demonstrated the ability of HCQ to attenuate vertical transmission of ZIKV by reducing placental and fetal infection. In this study, pregnant mice were treated with 40 mg/kg/day HCQ via intraperitoneal injection beginning one day after ZIKV infection. It was seen that HCQ acted as an autophagy inhibitor by increasing p62 levels in trophoblast and thus reducing placental ZIKV infection and fetal growth defects [31]. To date, no clinical trials have been conducted to evaluate HCQ antiviral effects in patients infected by ZIKV.