TLR7 and COVID-19: Recent studies demonstrated that mutations of TLR3 and TLR7 and some of the downstream signaling molecules required for type I IFNs production are correlated with the severity of COVID-19, indicating the critical roles of TLR3 and TLR7 signaling in the control of SARS-CoV-2 (Asano et al., 2021; Laurent et al., 2022; van der Sluis et al., 2022; Zhang et al., 2020).