Determination of diphtheria risk indicators based on the study of antidiphtheria immunity in the population of Dnipropetrovsk region

Abstract

Background. Vaccination is the most effective part of primary prevention. Serological monitoring of infectious diseases covered by national immunization programs is very important as it provides up-to-date information on the burden of the infection and the immunological status of the population. The study was aimed to present an analysis of epidemiological monitoring of the protection against diphtheria of the population, to show the generalized epidemiological situation regarding diphtheria, and to determine the risk of diphtheria among the population of Dnipropetrovsk region. Materials and methods. Epidemiological analysis of diphtheria immunity (2017–2019) was performed based on the results of enzyme-linked immunosorbent assay of IgG antibodies levels against diphtheria toxin in 271 residents of Dnipropetrovsk region. Results. Analysis of the results revealed that only 30.6 % (n = 83) of the population have levels of antitoxic antibodies of 1.0 IU/ml or more, which provides sufficient protection against diphtheria in the next 5–7 years of life. At that time, the majority of the population (69.4 %) needs immediate one-time booster vaccination (n = 134; 49.5 %) or immediate basic vaccination (n = 54; 19.9 %) due to low levels of antitoxic diphtheria antibodies. In the age group 8–15 years, 65.9 % (n = 62) of patients require immediate basic or booster vaccination, which indicates that children of this age do not have basic immunological protection due to violations of the vaccination schedule or its absence. In the group aged 27 years and older, 79.1 % (n = 72) of the subjects do not have protective levels of anti-diphtheria antibodies, which indicates a lack of actual protection against diphtheria. Conclusions. The results indicate insufficient protection of the population against diphtheria. In this regard, the development of strategic measures for mass immunoprophylaxis of diphtheria both in children and adults is relevant. The country should conduct regular epidemiological monitoring, which would study the population’s immunity against diphtheria and other controlled infections, and draw up a long-term strategic and tactical plan to address shortcomings in the work of mass immunoprophylaxis of the population.

Keywords

• population immunity, diphtheria, vaccination, antibodies