In 2000, the use of Oral polio vaccine (OPV) was discontinued in the U.S. to eliminate the risk of vaccine-derived poliovirus that can occur with OPV use. This decision was also based on the decreased risk of wild poliovirus being brought into the country and because the U.S. is currently polio-free.

The Centers for Disease Control and Prevention (CDC) recommended that children get 4 doses of polio vaccine to protect them against severe polio disease, including paralysis. Inactivated polio vaccine (IPV) is the only polio vaccine that has been given in the United States since 2000. Oral polio vaccine (OPV) is used in other countries.