An Overview of Vaccine-Derived Poliovirus
(also known as poliomyelitis or infantile paralysis) is an illness caused by poliovirus
. At one time, poliovirus infection occurred throughout the world. In about 1 percent of cases, polio disease can result in paralysis.
In 2000, oral poliovirus vaccine no longer was recommended in the United States for preventing polio because of the rare risk of vaccine-associated paralytic poliomyelitis.
Vaccine-associated paralytic poliomyelitis is an illness that is caused by vaccine-derived poliovirus.
What Is Vaccine-Derived Poliovirus?
A vaccine-derived poliovirus is a strain of poliovirus, initially contained in the live oral polio vaccine, that has changed over time; it behaves more like a wild or naturally occurring virus. This means that it can be more easily spread to others who are unvaccinated against polio and who come in contact with the stool or oral secretions, such as saliva, of an infected person. These viruses may cause illness, including paralytic poliomyelitis.
Occurrence of Vaccine-Derived Poliovirus
In 2005, a vaccine-derived poliovirus was found in the stool of an unvaccinated child in the state of Minnesota. The child most likely caught the virus through contact in the community with someone who received live oral vaccine in another country.
Because oral poliovirus vaccine has not been used in the United States since 2000, it is likely that any vaccine-derived poliovirus seen in the United States would have come from a person who received oral poliovirus vaccine in another country. Oral poliovirus vaccine is used in many countries of the world, including Central and South America, Africa, and Asia.
Vaccine-Derived Poliovirus: Should You Be Concerned?
can protect people against naturally occurring polioviruses and vaccine-derived polioviruses. It is unlikely that a vaccine-derived poliovirus
would become widespread, because most people in the United States have received polio
vaccinations. Most vaccine-derived polioviruses disappear over time without causing any clinical disease. Very rarely, usually in communities where routine polio immunization has been low, vaccine-derived polioviruses have spread beyond close contacts.
Over the past decade, more than ten billion doses of oral polio vaccine
have been given worldwide, with only six outbreaks of circulating vaccine-derived polioviruses confirmed, resulting in approximately 50 cases of paralytic polio. People who are not up to date with polio immunizations should talk with their healthcare provider.