Multivariate analysis of the megacity population immunity to measles

Abstract

Background: The significant reduction of measles and rubella morbidity and child mortality, which allowed WHO to set a target for their elimination by 2010, is one of the finest examples of the vaccine prevention effectiveness in the fight against infectious diseases. However, in the period from 2010 to 2019 there was a controversial situation with respect to measles, characterized by the presence of high vaccination coverage of the population on the one hand, and an increase in the incidence on the other. Obviously, the key point in resolving these contradictions is to analyze the susceptibility of the population.
 Aim: Of the study was to assess the susceptibility of Moscow population to measles in the context of factors affecting its formationю.
 Methods: Epidemiological, serological, statistical methods and GIS technologies were used in the work. The serological study (using the solid-phase ELISA method) included 2410 blood serum samples collected between 2013 and 2017 from healthy residents of Moscow aged from birth to 60 years. On the basis of documents on sanitary and epidemic investigation of measles cases in Moscow (20132015) a relational database under the management of MySQL Database Management System was formed, based on the analysis of which the coverage of the population with preventive vaccinations was estimated.
 Results: Оn average, the proportion of seronegative persons to measles in 20162017, compared with 20132014 (20.5%) increased and amounted to 29.0% mainly due to the group over 36 years. The most vulnerable were children aged 12 years and 36 years, where the share of the immune persons amounted to 51,5% and 37.9%, respectively, at low coverage in a planned manner (55,9% [95% CI, 52.2 per cent; of 59.5%] and 75,3% [95% CI, 73.3 per cent; for 77.2%]). The proportion of vaccinated persons who lost post-vaccination immunity under the influence of factors preventing its formation (from 3.6% to 21.6% in the group of 714 years; from 11.8% to 26.4% in the group of 1517 years) was calculated. The possibility of visualizing the spread of measles on electronic maps for the territorial and temporal analysis of the epidemic situation is shown.
 Conclusions: It is reasonable to assume that over the time, the proportion of people who have suffered measles will decrease, and the proportion of people not covered by vaccination or lost post-vaccination immunity - increase, that can lead to a decrease in herd immunity and requires correction of vaccination work. The proposed information and analytical system for monitoring the epidemiological situation allows to work quickly with heterogeneous resources and choose on electronic maps the area of interest from the global level (country) to the local (house), which is necessary for the adoption of scientifically based preventive and epidemiological measures.