State of anti-rubella virus population immunity in the Republic of Belarus and Russian Federation

Abstract

To confirm a progress towards the rubella elimination, immunization coverage indicators and the results of serological studies are used. At the same time, the most objective method of assessing collective immunity is a serological examination. The purpose of this work was to compare the results of assessing state of population immunity against rubella virus in the Republic of Belarus and the Russian Federation using various vaccines and different approaches to study organization and cohort selection screening and monitoring. 2019 laboratory studies to determine IgG antibodies against rubella virus were carried out by ELISA method of the unified enzyme immunoassay system Ecolab (Russia). The serum study results of 701 subjects aged 245 years from all the 7 regions of the Republic of Belarus (screening study) and 55 082 subjects aged 349 years (monitoring) from 85 regions of the Russian Federation were analyzed. The results were evaluated in three age groups children, adults, total cohort by using a threshold level of 8385% seropositive individuals sufficient to prevent virus transmission. The antigenic composition of the rubella component in the mono- and complex vaccines respectively used in the Russian Federation and the Republic of Belarus is identical, which allows to compare the state of population immunity against rubella virus therein without taking into account an influence of the vaccine strain. Studies have shown that while using varying vaccine preparations and approaches to organization of serological examination, both in the Republic of Belarus and the Russian Federation, rubella virus-specific IgG level was detected at rather high level in all age groups comprising more than 90%. The portion of rubella seropositive subjects in entire country was 95.44% in the Republic of Belarus and 97.14% in the Russian Federation. Moreover, the level of specific antibodies remains high, despite the low incidence rate and absence of booster effect in both countries. The mean group antibody concentration in seropositive patients in all age groups was quite high and exceeded the minimum protective concentration (11 IU/ml) by 10 or more times. The data obtained indicate the legitimacy of using a serological study of collective rubella immunity as a routine or seromonitoring as well as periodic or screening investigation.