CD147 was identified as a broad receptor mediating infection of SARS-CoV-2 and its variants Alpha, Beta, Gamma, and Delta.26–28 The silencing of CD147 showed similar inhibitory effect on infection of SARS-CoV-2 as Bromhexine hydrochloride, a specific inhibitor of TMPRSS2 (Supplementary Fig. 11). Here, TMPRSS2 is linked to infection.