Response of Infants to a Third Dose of Poliomyelitis Vaccine Given 10 to 12 Months after Primary Immunization

Abstract

IMMUNIZATION AGAINST POLIOMYELITIS BAJn in December, 1956, with the most highly attenuated currently available strains of each of the three types, have thus far produced no untoward reactions in vaccinees or their contacts. Spread of the vaccine viruses to others is an accepted fact in the immunization with live poliovirus vaccines, and this problem is not being "side-stepped " but is rather being carefully studied in various trials. The trials on some hundreds of thousands of children-some already completed, others now in progress, and still others to be initiated in 1959-carried out in accord with the stipulations of the Expert Committee on Poliomyelitis of the World Health Organization should provide us in the near future with the information necessary for a decision regarding the place of orally administered live poliovirus vaccines in the prevention and eradication of poliomyelitis.