RESUMEN
The analysis of pertussis morbidity and the state of immunity to pertussis has made it possible to evaluate the existing epidemiological situation as unfavorable. The restraining influence of specific prophylaxis on the epidemic process of pertussis becomes weaker due to the growing number of nonimmunized children; for this reason, the maximum morbidity rate in pertussis is observed among children under 5 years of age, as it was at the period before the introduction of mass immunization against pertussis. To prevent further possible increase in the intensity of the epidemic process of pertussis and in the severity of the clinical course of the disease, the number of children under 3 years of age, not immunized against pertussis, must be reduced by limiting the number of children exempted from immunization on medical grounds and by increasing the proportion of children immunized from the age of 3 months.