Yes, like other vaccination, polio vaccination also used to be injectable(IPV). Oral polio vaccine is a live-attenuated vaccine, produced by non-human cells at a sub-physiological temperature. OPV produces excellent immunity in the intestine, the primary site of wild poliovirus entry. IPV produces less gastrointestinal immunity than does OPV, so persons who receive IPV are more easily infected with wild poliovirus. Immunity initiated by OPV is probably lifelong.