The socially dangerous diseases comprise tuberculosis, HIV-infection, parenteral hepatitis and sexually transmitted infections. Per se they are ultimately different diseases. The only connecting link between them is their social component. It is possible to consider whole social component as a unity of "social input" allowing evaluating the effect of social factors on beginning and maintenance of epidemic process. Furthermore, this component can be also considered as "a social response" resulting propagation of infections throughout society. In this case, it becomes clear that social character of tuberculosis infection is more manifested at the level of "social input" than "social response". This pattern is conditioned by the characteristics of pathogenesis of tuberculosis infection. "The social input" effects on both development of disease and its maintenance in society on the stage of becoming of recurrences of tuberculosis disease. At the same time, the burden of "social response" of society to infection is significantly lower in case of tuberculosis than under HIV-infection and parenteral hepatitis. This occurrence is also related to lesser effect on demographic indicators and small "unprofitability" of disease as compared with hemocontact infections.