In vitro har maraviroc ingen aktivitet mod virus, der bruger CXCR4 som deres indtrædende co - receptor (dual- tropisme eller CXCR4- tropisme, der tilsammen benævnes CXCR4- using virus, se nedenfor).
Maraviroc has no antiviral activity in vitro against viruses which can use CXCR4 as their entry co- receptor (dual-tropic or CXCR4-tropic viruses, collectively termed ‘ CXCR4-using’ virus below).