The poliomyelitis (polio) vaccine protects against poliovirus infections. The vaccine helps the body produce antibodies (protective substances) that will prevent an individual from contracting polio. There are two forms of the vaccine that can be given; the one preferred is the inactivated poliovirus vaccine (IPV). IPV is preferred because it contains the inactivated or dead virus, which is considered safer for administration. The Sabin oral polio vaccine was made with a live but weakened virus, which gives the advantage of passive immunity for large groups (i.e. because it is easily passed on through the oral fecal route in households, schoolrooms, etc., even if only a portion of the community is immunized, everyone eventually develops immunity). The Sabin oral polio vaccine has the disadvantage of causing polio-like symptoms in some immune compromised hosts. Since 2000, the live virus vaccine is rarely used in the United States, but it is still being used in other countries.
The purpose of any vaccine is to prevent disease. Mass immunizations in the United States have served to eradicate polio in the Americas. In 1988, the World Health Organization embarked upon a mission to eradicate polio by the year 2000. The intent was to immunize the world's children by methodically establishing sites where the masses could be reached. The mandate was to eradicate the virus by 2005. Most of the remaining virus can be found on the Indian subcontinent and Nigeria. Attempts to immunize children in Indian have met with good results, but Nigeria halted their immunization sites due to rumors that Western donors had tampered with the vaccine to spread HIV and cause sterility in Muslim males. Following a ban on the vaccine that lasted nearly one year, the virus spread across Nigeria to 10 African countries that were previously polio-free. The Muslim leaders in Nigeria lifted the ban in summer 2004. Immunization from the IPV triggers an excellent immune response and long-lasting immunity to all three poliovirus types.
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Author Info: Linda K. Bennington MSN, CNS, Thomson Gale, Gale, Detroit, Gale Encyclopedia of Children's Health, 2006 |