ultimate motive of vaccination let it b pre or post is to stimulate ur immune system to make anybody against a germ..if u r completing post exposure prophylaxis which is little more quick than pre exposure (since we hv enough time) in stimulating ur immune system. all u need to do aftr completion of post exposure prophylaxis is take booster dose aftr every 3 or 5 years...if no dogs bite u in beween if unfortunately ur bitten by dog in dis period..though body has its immunity still u need to take post exposure prophylaxis got it?