The only approved polio vaccine in the United States is an injectable vaccine. An oral polio vaccine was discontinued in 2000. The oral vaccine contained a weakened virus, which rarely led to the full-blown paralytic polioourelitis. The injectable vaccine contains a killed virus, and it is impossible to get polio from that vaccine. The polio vaccine can be given separately or in a combination vaccine with other vaccines.
The recommended dosing schedule for the polio vaccine is two and four months, with another dose at six to eighteen months and a booster dose at four to six years. In addition, adult travelers to areas of the world where polio is still common are recommended to get a booster dose. The two countries with the most cases in recent years have been India and Nigeria, but many countries in Asia and Africa have had some cases.