An in vivo study found that CQ could exert anti-HCoV-OC43 activity transplacentally or via maternal milk. The data from mouse models showed that 98.6% of the pups survived when pregnant mice were treated with 15 mg/kg of CQ, and survival rates decreased in a dose-dependent manner, with 88% and 13% survival when treated with 5 mg/kg and 1 mg/kg CQ, respectively [14]. The survival rate of newborn mice via maternal milk was 69.0% with 15 mg/kg of CQ [14]. In another mouse study, CQ strongly attenuated HCoV-OC43 replication in the brain and prevented the infection from spreading to the spinal cord [15]. The above studies confirmed that CQ/HCQ have a broad-spectrum anti-HCoV activity in vitro and in vivo.