Standing at the metal double door
You can see them lined up
The Oral Polio Vaccine (OPV) was developed in 1958 by Dr. Albert Sabin. Sabin attenuated the wild type poliovirus by passaging the virus in monkey kidney epithelial cells. Trivalent OPV is characterized in vivo by efficient growth properties in the intestinal tract, unaltered immunogenic properties with respect to wild type progenitors, and attenuated neurovirulence after experimental intraspinal injection into primates. This means that an individual immunized with trivalent OPV induces long-lasting (frequently life-long) protective immunity of the gastrointestinal tract to all known forms of poliovirus.
Little hands outstretched
For consecrated sugar cubes
A year later Dr. Alber Sabin worked on a live-virus polio vaccine. In 1961 the American Medical Association endorsed the use of Sabin's oral vaccine. Upon the adoption of the Sabin vaccine, everyone in America was called back for immunization.
Changelings now, free from
Disease that paralyzed limbs
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).
They walk out of the Gymnasium
Into the world: Soldiers of Immunity