Population immunity to measles, rubella, and mumps viruses

In the post-pandemic period, in 2023–2024, high incidences of measles were recorded in all regions and countries worldwide, and there was a marked increase in cases of rubella and mumps. It is believed that double vaccination and high vaccination rates guarantee the elimination of measles and rubella. However, the true state of population immunity is determined by the results of immunological (serological) monitoring. The aim of the study was to assess the strength of humoral immunity to measles, mumps, and rubella in adults depending on age and previous vaccinations. Materials and methods. The study involved 3,617 informed participants from three regions within the Federal Medical and Biological Agency (FMBA) system, divided into five age groups (I – 18–27, II – 28–37, III – 38–47, IV – 48–57, V – 58 and above). All participants had their health status (presence of chronic diseases) and vaccination history against measles, rubella, and mumps analyzed. Their blood serum was tested for IgG antibodies to these viruses using the ELISA test systems VectoMeasles-IgG, VectoRubella-IgG, and VectoParotitis-IgG (Vector-Best). Antibody levels were defined as non-protective, low, moderate, and high. Results. Of the 3,617 subjects examined, 27.8% did not have a protective antibody titer to measles, 13,3% to mumps, and 3,9% to rubella (P < 0,001). A significant increase in the number of people unprotected against measles was revealed among young people: 47.1% in the 18–27 age group, 41,9% in groups II, 35,5% in III, and 21,6% in IV, which creates conditions for disease outbreaks. Only in people over 58 years of age did unprotected titers have 3,2%, and in this group there was the highest number of people with high antibody titers – 11,2%, in contrast to the other groups (p < 0,05). The highest proportion of people unprotected against mumps was in the 28–37 age group – 19,3% and 38–47 years – 20,1%. The situation with rubella remains epidemically stable. Conclusion. The obtained data confirm the feasibility of the planned introduction of additional immunization against measles and mumps for people aged 18–47 years and the expansion of seromonitoring of all three infections in adults aged 18–47 years.