What is polio vaccine and is it safe?
Polio vaccine protects people against polio. There are two types of polio vaccine: Inactivated polio vaccine, called IPV, which is given as a shot (the polio virus used in this vaccine is killed); and live oral polio vaccine, called OPV, which is a liquid that is swallowed (the virus used in this vaccine is attenuated or weakened). Currently in the U.S. we use only IPV, but in parts of the world where polio still exists people get vaccinated with OPV. Both OPV and IPV protect against polio, but OPV is better at keeping the disease from spreading to other people. However, in rare cases (about 1 in 2.4 million), OPV actually causes polio. Since the risk of getting polio in the U.S. is now rare, experts believe that the benefits of OPV no longer outweigh the slight risks. IPV does not cause polio or any other serious problems. Some people who get IPV get a sore spot where the shot was given, but most don’t have any problems at all with it.
