INFLUENCE OF POPULATION IMMUNITY PECULIARITIES ON THE STRUCTURE OF MEASLES AND RUBELLA PREVALENCE

Abstract

According to the lasting serological investigations of patients with rubella and measles, a major factor that determines the resistance to the infections is specific antibodies, that are still circulating in blood of recovered persons during their life. Since vaccinated people are also included in this concept, serological monitoring of people different ages who get vaccinated against rubella and measles is conducted in Russia. However the discrepancy between specific immunity intensity and the measles incidence was showed last years. Using “Vector Best” kits, the study of the anti-measles and antirubella population immunity in scale of age: under 1 year, 1–2 years, 3–6 years, 7–14 years, 15–17 years, 18–30 years, 31–40 years, 41–50 years, and 51–60 years was carried out in Moscow and Moscow region in 2013 (period of unfavorable epidemic situation). The serum probes were obtained from 654 random healthy donors and 646 patients with serologically confirmed measles infection. As a result, gradual increase of percentage of people with protective antibodies to rubella and measles have been demonstrated: 81.3% donors aged 7–14 years were protected from measles and more than 90% — from rubella. Moreover, percentage of individuals who have had immunity to rubella were the same in adults too. The most marked increase of percentage of seronegative persons to measles virus (40% and more) was in age from 18 to 30 years, and in groups over the age 40 years old protection reaches 85–95%. Comparison between percentage of measles patients different ages and percentage of persons with protective antibodies in serum have demonstrated significant negative correlation between measles prevalence and the level of specific antibody in population (r = –0.76). According to the results, increase (to 28%) and decrease (to 2.9%) of measles patients aged 18 to 30 and 51 to 60 years are based on decrease (to 55%) and increase (to 95%) of persons with protective immunity, respectively. Results of analysis of measles prevalence in different ages have demonstrated, that among adult measles patients (18–50 years) 14.5% responded on infection by secondary immune response; among children and teenagers there were no such patients, that proves the significant effectiveness of prophylactic vaccines.

Keywords

• measles
• rubella
• antibodies
• population immunity
• prevalence
• seromonitoring