Аңдатпа
Introduction. Mass vaccination, implemented in Russia within the framework of the Russia National Vaccination Calendar, is a key component in the fight against vaccine-preventable infections (measles, mumps, rubella). The aim. The study’s aim was to assess herd immunity to the most common vaccine-preventable infections in several Russian regions. Materials and methods. The study involved 18 247 volunteers from several regions (Amur, Irkutsk, Nizhny Novgorod, Kaliningrad) and the Republic of Crimea. During the study, participants completed a questionnaire. A cohort of volunteers, stratified by age (1–5, 6–11, 12–17, 18–29, 30–39, 40–49, 50–59, 60–69, ≥ 70 years), was randomized using a web application. Antibodies to the measles, rubella, mumps were quantitated by ELISA (IgG) using Russian-made test systems. Results. The cohort average seropositivity magnitude for measles, mumps, and rubella were 75.7%, 84.0%, and 95.8%, respectively. For measles, the highest seropositivity level was observed in the group 1–11 years (Me = 74.8%; IQR = 68.5–83.5) and the group 60–70+ years (95.1%; IQR = = 93.2–95.8). Regarding mumps, these two ago groups also showed peak values: 1–11 years (Me = 85.9%; IQR = 81.4–92.5) and 60–70+ years (Me = 88.6%; IQR = 83.7–90.6). The lowest measles seroprevalence was observed in 18–39-year age group (Me = 59.7%; IQR = 55.9–64.6). For mumps, the lowest seroprevalence was also observed in 18–39-year age group (Me = 78.4%; IQR = 63.9–83.7). Regarding rubella, seropositivity was evenly distributed across the entire cohort: Me = 95.8% (IQR = 93.9–97.5). Among specific vaccines for immunization against measles/mumps or rubella, the mumps-measles or live monovalent rubella vaccine, respectively, was most or more frequently used. Conclusion. High measles and mumps seroprevalence among children is due to post-vaccination immunity following mass immunization, primarily with the mumps-measles vaccine. Seroprevalence in older adults is associated with childhood infections that have elicited post-infectious immunity. Rubella immunity was virtually independent of age, geographic location, or climate factors. Reduced measles and mumps seropositivity among middle-aged individuals may lead to emergence of sporadic cases of these diseases, which may require additional measures, including catch-up vaccination.