Poliomyelitis

Poliomyelitis, or polio, is a virus that causes a serious disease. It is spread from person to person. 
Most of the time, polio has no symptoms unless the polio virus gets into the blood. It is uncommon for the virus to enter the brain or spinal cord. If this does happen, it can cause muscles to become paralyzed. Some people get better from the paralysis. Others will be disabled. Depending on which muscles have been affected, these people may need a mobility aid or a wheelchair; they may have difficulty using their hands; or they may even have trouble breathing. 
About 15 out of every 10,000 adults who get polio die. (This means an adult has a 0.015% chance of dying from polio.) 
Vaccination with polio vaccines could stop the disease all over the world. Organizations like the World Health Organization have been trying to vaccinate as many people as possible against polio. Vaccinations have eliminated polio from most countries in the world. 
Worldwide, polio has become much less common in the past few decades. In 1988, there were about 350,000 cases of polio in the world. By 2007, the number of cases of polio in the world had decreased by over 99.9%, to just 1,652 cases.
The disease is preventable with the polio vaccine; however, multiple doses are required for it to be effective. The US Centers for Disease Control and Prevention recommends polio vaccination boosters for travellers and those who live in countries where the disease is endemic.
The 32nd President of the United States, Franklin Delano Roosevelt, had polio. So far, he is the only President of the United States to have had this disease.
Prevention.
The way to prevent polio has been known for many years:
1. Vaccine given 6, 12 and 16 weeks old as part of a six-in-one vaccine.
2. Three years and four months old as part of a 4-in-one pre-school booster
3. 14 years old as a part of the 3-in-one teenage booster.
The child has to have ALL of these to be fully protected. 
This complicated list explains why polio is still around. In endemic areas, wild polioviruses can infect virtually the entire human population. Not all, however, develop paralysis or any other sign of the infection.
The vaccine was developed by Jonas Salk in the 1950s.