Oral Polio Vaccine

Oral polio vaccine, which contains live but weakened poliovirus, is highly effective in preventing polio. However, because it poses a very slight risk of a rare but serious condition (vaccine-associated paralytic poliomyelitis), its use in the United States has been discontinued -- an enhanced-potency inactivated polio vaccine is now used instead. Oral polio vaccine is still used for polio prevention in many other parts of the world.

 

Oral Polio Vaccine: An Overview

Oral polio vaccine (OPV) is a vaccine that contains live but weakened poliovirus. Oral polio vaccine is highly effective in polio prevention. However, because of the risk of a rare but serious condition called vaccine-associated paralytic poliomyelitis, oral polio vaccine use in the United States was discontinued in 2000.
 

History of Polio and Oral Polio Vaccine

A 1916 polio epidemic in the United States killed 6,000 people and paralyzed 27,000 more. In the early 1950s, there were more than 20,000 cases of polio each year.
 
The first polio vaccine was licensed in 1955. This polio vaccine was an inactivated polio vaccine (IPV), meaning it did not contain any live poliovirus. By 1960, the number of cases had dropped to about 3,000. In 1961, an oral polio vaccine was licensed. Following its introduction, as the number of polio cases continued to drop. In 1979, the last cases of paralytic poliomyelitis caused by wild poliovirus in the United States occurred. The success of polio vaccination in the United States and other countries sparked a worldwide effort to eliminate polio.
 
In 1998, an enhanced-potency inactivated polio vaccine became available. Because oral polio vaccine can cause a rare but serious reaction called vaccine-associated paralytic poliomyelitis, it was recommended that oral polio vaccine not be used. In 2000, the use of oral polio vaccine in the Unites States was discontinued.
 

How Effective Is Oral Polio Vaccine?

Oral polio vaccine is highly effective in producing immunity to poliovirus. A single dose of oral polio vaccine produces immunity in approximately 50 percent of recipients. Three doses of oral polio vaccine will produce immunity to all three poliovirus types in more than 95 percent of recipients. As with other live-virus vaccines, immunity from oral polio vaccine is probably life-long.
 
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Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;