Booster effect of Sabin poliomyelitis vaccine.

Studies were carried out on 86 children aged 1-14 years who had titres of antibodies against poliovirus type 3 lower than 1: 32 and against type 2 higher than 1: 4. After a booster dose of poliomyelitis vaccine type 2+3, seroconversion took place in 44 (90%) of 49 children whose original titre was lower than 1: 4 and the geometrical mean titre increased to 1: 244. Of 37 children with low original titres of antibodies against type 3, i.e., 1: 4, 1: 8, or 1: 16, the titre increased fourfold or more in 31 (84%) and the geometrical mean titre rose to 1: 175. In 11 children (13%), no significant increase in titre took place.