[Functional state of specific immunity in children and teenagers vaccinated against mumps]

Abstract

The functional state of immunity was evaluated from the avidity index (AI) of specific antibodies (IgG) and the level and spectrum of their neutralizing activity. The study recruited 200 subjects immunized with Russian vaccine against mumps according to the mandatory scheme. A group of vaccinees with a low AI of specific IgG was identified mainly among old children and teenagers. The vaccinees with a low AI had a significantly lower protective immunity (as shown from the level and spectrum of serum neutralizing activity) than those with a high AI. The vacinees with no humoral, incomplete, or complete postvaccination immunity, but with a low AI of specific IgG, can constitute a population stratum that preserves sensitivity to wild-type mumps viruses and serves as a favorable medium for their circulation.