Before revision:  Our results indicate that heparin is able to inhibit SARS-CoV-2 infection by allosterically hindering binding to the host cell receptor, by directly competing with binding to the host heparan sulfate proteoglycan co-receptors, and by preventing spike cleavage by furin .
After revision:  Our results indicate that heparin exerts its antiviral activity by both direct and allosteric mechanisms .