Updated: February 13, 2008
Polio is caused by intestinal viruses that spread from person to person in stool and saliva. Most people infected with polio (approximately 95%) show no symptoms. Minor symptoms can include sore throat, low-grade fever, nausea, and vomiting. Some infected persons (1 to 2%) will have stiffness in the neck, back, or legs without paralysis. Less than 1% of polio infections (about 1 of every 1,000 cases) cause paralysis. In some cases, the poliovirus will paralyze the muscles used to breathe, leaving the victim unable to breathe on his or her own. Many paralyzed persons recover completely. Those who do recover from paralytic polio may be affected 30 to 40 years later, with muscle pain and progressive weakness.
Before the polio vaccine, 13,000 to 20,000 people were paralyzed by polio, and about 1,000 people died from it each year in the United States. Most of those infected were elementary school children so it was often called ‘infantile paralysis.’
The incidence of paralytic polio peaked in the U.S. in 1952 with 21,000 reported cases and numerous deaths. Following licensure of the Salk (inactivated) polio vaccine in 1955, the incidence of the disease fell dramatically. The disease was further reduced by the advent of the Sabin (oral) polio vaccine in 1961. The last cases of paralytic polio from natural poliovirus in the U.S. were in 1979, and the most recent case from outside the U.S. occurred in 1993.
Today, polio has been eliminated from the U.S. and the entire Western Hemisphere, although it remains a threat in some countries. The World Health Organization set up an initiative to eradicate polio from the planet by the end of 2005.
The polio vaccine is available as:
Product: IPOL® (Polio Vaccine Inactivated-IPV)
Manufacturer: Aventis Pasteur
Year licensed: 1990
Product Name: PediarixTM (IPV, DTaP, and hepatitis B vaccines)
Year licensed: 2002
The oral polio vaccine (OPV) is no longer administered in the U.S.
For information on the thimerosal content in these vaccines, see:
Two types of polio vaccine (OPV, oral polio vaccine, and IPV, inactivated polio vaccine) were created in the 1950s. Both were highly effective in preventing polio. Initially OPV was preferred because it helped to increase community immunity to polio.
However, about 1 out of 2.4 million doses of OPV distributed in the United States actually caused vaccine-associated paralytic polio (VAPP). In an effort to reduce this terrible side effect, a new polio vaccine schedule was recommended in 1997 (two doses of IPV followed by two doses of OPV). The new schedule decreased, but did not guarantee elimination, of vaccine-induced paralytic polio; so, effective in the year 2000, an all-IPV schedule was recommended, and OPV is no longer administered in the U.S. OPV continues to be used in countries where wild polio infections still occur.
Who should receive the inactivated polio vaccine?
Who should receive the oral polio vaccine?
Who should not receive the vaccine?
This vaccine is recommended by:
The complete childhood immunization schedule for the U.S. can be found at:
The summary of adolescent/adult immunization recommendations can be found at: www.cdc.gov/nip/recs/adult-schedule.pdf
In the U.S., inactivated polio vaccine (IPV) is recommended.
Children should receive doses of IPV—or IPV combined with the DTaP and hepatitis B vaccines (PediarixTM1, GlaxoSmithKline)—at two months, four months, and 6 to 18 months. A booster dose of IPV (not a combination vaccine) is given at four to six years.
Young adults who have never been vaccinated against polio may receive the first dose of IPV (not a combination vaccine) at any time. The second dose should be given one to two months later, and third dose 6 to 12 months after the second.
Adults who have never been immunized and who are traveling to areas where polio outbreaks occur can receive three doses of IPV, each given four weeks apart.
The IPV vaccine is 90% effective after two doses and 99% effective after three doses. Duration of immunity is unknown at this time, though it is probably quite long.
Most people have no side effects at all. Some people have soreness where the shot is given. IPV is not known to cause any serious side effects. However, if a serious allergic reaction occurs, it happens within a few minutes to a few hours after the shot. Signs of a serious allergic reaction can include difficulty breathing, weakness, hoarseness or wheezing, a fast heart beat, hives, dizziness, extreme paleness, or swelling of the throat.
OPV causes vaccine associated paralytic polio in a very small percentage of those immunized. It is more likely to occur in those with weakened immune systems. IPV cannot cause paralysis, as the vaccine virus has been inactivated.
Batches of polio vaccine used between 1955 and 1963 were later found to be contaminated with a virus that infects monkeys, called simian virus 40 (SV40). Studies to date have shown that those who received OPV containing SV40 are not at additional risk of complications, though scientific research is continuing. OPV produced since 1963 does not contain SV40.