Математическое обоснование возможности элиминации кори в России

17.02.2009

Резюме

В статье приводятся результаты исследований, выявившие, что за последние 50 лет в эпидемическом процессе кори произошли существенные качественные и количественные изменения. Начавшаяся в 1967 году вакцинация против кори на протяжении десятилетий меняла свою тактику. В настоящее время заболеваемость корью в стране впервые стабилизировалась на показателях менее 1,0 на 100 тыс. Сопоставление экспериментальных данных математической модели с фактическими данными свидетельствует о том, что в настоящий момент достигнуто эпидемическое равновесие, при котором скорость инфицирования восприимчивых индивидов уравновешивается скоростью появления новых восприимчивых индивидов за счет новорожденных, потери иммунитета или иммиграции, что характерно для начальной фазы элиминации кори.

Summary

The specific prophylaxis against measles which has been implemented in the Russian Federation brought about qualitative and quantitative changes to the epidemic process. The objective of this paper is to trace these changes over the last fifty years (1957 - 2007) and to substantiate the feasibility of eliminating measles in Russia. In the stage of measles elimination the average age of infected persons has stabilized at 21.7 years that shows the decreasing role of the children's population in producing and spreading the infection in the population that is an indicator of successful immunization. This is evidenced by the factual data of incidence: the proportion of children under the age of 14 years among the infected patients averaged 29.04% and in the last three years this figure was not more than 19.7%. The rate of measles infection propagation decreased from 0.28 in the period when there was no effective measles vaccine to 0.05 in the elimination period. During this period the estimated number of secondary measles cases declined more than two times and averaged 4.0, in the last few years it didn't exceed 1. The spread of infection reduced drastically and it doesn't produce more than 2 generations. This data shows that the immunization level in children, as well as in adults, is over the critical one and the causative agent is incapable to propagate in the population. The rate of infection propagation in Russia is represented by the factor R < 1 that points to the fact that the infection has been eliminated.

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