To eliminate the risk for vaccine-associated paralytic poliomyelitis (VAPP), the Advisory Committee on Immunization Practices (ACIP) has recommended an all inactivated poliovirus vaccine (IPV) schedule for routine childhood polio vaccination in the United States. As of January 1, 2000, all children should receive four doses of IPV at ages: 2 months, 4 months, 6-18 months, and 4-6 years. Oral polio vaccine (OPV) should be used only for the following special circumstances: -Mass vaccination campaigns to control outbreaks of paralytic polio. -Unvaccinated children who will be traveling in less than four weeks to areas where polio is endemic. -Children of parents who do not accept the recommended number of vaccine injections. These children may receive OPV only for the third or fourth dose or both; in this situation, health-care providers should administer OPV only after discussing the risk for VAPP with parents or caregivers. Source: Centers for Disease Control and Prevention

Although records from antiquity mention crippling diseases, it was Michael Underwood who, in 1789, first described polio. Poliomyelitis, commonly known as polio, became an epidemic disease in the United States at the turn of the century, ravaging tens of thousands of lives each summer and fall. Polio rapidly declined following the discovery of the polio vaccine, and the last case of viral acquired polio in the U.S. was in 1979.

What happens in polio?

Polio is spread by the fecal-oral route. This means that the virus is spread directly from the stool of an infected person to the mouth of another person, probably from contaminated hands.

Inanimate objects, such as eating utensils, may also spread the virus. Infection with poliovirus results in a spectrum of symptoms ranging from a cold like illness, to aseptic meningitis, paralysis, and death.

The virus enters the mouth and once inside the intestinal tract, the virus multiplies. From there it spreads to the lymph nodes, then enters the blood stream. The virus then attacks the nervous system and can cause paralysis in legs or other parts of the body. Most poliovirus infections are asymptomatic. Following the acute episode, many people recover muscle functions at least partially.

How to prevent it

Oral Polio Vaccine

The oral polio vaccine (OPV) essentially erased the fear of polio, virtually eliminating it in the United States in a few short years. Today, however, the risks of using OPV are proving to outweigh the benefits. In the last 17 years, the only cases of polio in this country have been due to the oral vaccine.

Following the administration of OPV, a live-weakened form of the poliovirus, there have been rare cases of vaccine associated paralytic poliomyelitis (VAPP). It is thought that the virus mutates while in the intestine forming a more virulent strain capable of causing paralysis.

Vaccine related polio may also be spread from the person to person. The polio virus replicates in the gut and is shed in the stool, so someone who changes diapers of small children may be exposed and infected.

Inactivated Polio Vaccine

The most important advantage of inactivated polio vaccine (IPV) is that cannot replicate in the intestine and cause VAPP or be shed in the stool of a vaccinated person. One disadvantage of IPV is that requires an injection and there are no combination vaccines available.

People who receive IPV are more easily infected in the intestines with wild polio virus than those who receive OPV. Someone who received IPV could become infected with wild polio while traveling and shed the virus when they return to the U.S. Polio is still common in other parts of the world where many people are not vaccinated. The vaccinated person would be protected from polio, but the virus in the intestine could be spread to others.

New Polio Vaccine Recommendations

The Centers for Disease Control and Prevention (CDC) is changing to an all IPV schedule beginning in January 2000, to completely eliminate the risk of VAPP while still providing protection against polio.

All children will still need to get four doses of the polio vaccine at ages 2 months, 4 months, 6 to 18 months, and 4 to 6 years. Until polio is eradicated - that goal is by the end of the year 2000, all children still need to be vaccinated for polio.