The persistance of immunity several years after primary immunization with live oral poliovirus vaccine Sabin

Abstract

Both humoral immunity and intestinal resistance in a group of children were followed 2 to 6 yr after primary immunization in Ivanjica, a small community in Serbia. A significant decrease in antibody titers was found for all 3 types of polioviruses, especially marked for type 3, 2 to 3 yr after primary immunization, where in approximately 20% of the examined persons it decreased to less than 1:4. After 4 to 5 yr the same trend was noticed. Intestinal resistance was examined 2, 3 and 6 yr after primary immunization in a group of 129 children. 36% of the children boostered with type one or trivalent vaccine could be reinfected, 46% of those revaccinated with type 2 or trivalent vaccine were susceptible and 41% of children refed type 3 or trivalent vaccine responded with virus excretion or antibody increase. (Journal received: 3rd May 1974)