The on-going evolution of the epidemic process is under active influence of a new regulatory risk factor, environmental pollution of technogenic origin. The negative influence of ecological pressure on the manifestations of infectious diseases is apparent as destabilization of the epidemic processes, increased severity of infections, impaired epidemiological and immunological efficacy of vaccine prophylaxis in the child population. The most vulnerable component in the epidemic process is the minimal period of infectious morbidity. As shown in an epidemiological experiment, it is in this period that especially active preventive measures must be taken to ensure efficacious management of infection.