This article is from the Childhood Vaccinations FAQ, by Lynn Gazis-Sax firstname.lastname@example.org with numerous contributions by others.
Oral polio vaccine provides better immunity, and was until recently
usually the recommended form, "because induces intestinal immunity, is
simple to administer, is well accepted by patients, results in
immunization of some contacts of vaccinated persons, and has a record
of having essentially eliminated disease associated with wild
poliovirus in this country." (PDR) However, it carries a small risk of
paralysis (see the answer to the next question for details).
Recently, with increased progress in worldwide eradication of polio,
both ACIP and AAP have changed their recommendation to IPV for all
shots. OPV remains the vaccine of choice for countries where polio is
still endemic, and for people who will be shortly travelling to such