"During taxi out...we were informed on the Ground frequency by Air Carrier B that one of their passengers deboarding behind us was 'blown down and injured' by our jet blast while departing the ramp. All three engines were running as I anticipated a short taxi. No more than idle thrust was required nor used as we were very light...I made approximately a 45-degree right turn toward taxiway before being released from guide person. We could not see, nor were we informed, of any boarding operation behind us. I believe Air Carrier B was remiss for allowing a deboarding operation behind a jet whose engines were running." (ACN 79190)