In the article there is presented the comparative analysis of the character of the specific humoral response to pertussis in dependence on the age, terms of the disease and vaccination history in 279 patients, among which 114 patients were under 1 and 165 patients - over 1 year of the age. In the study of the level of the production of antibodies of different isotypes in unvaccinated patients of different age in dependence on the terms of medical examination it has been revealed that in the patients under the age of 1 year there was typical the low production of all the classes of antibodies in any time of the disease, especially IgM. It has been shown that in babies aged from 0 to 3 and from 4 to 6 months old the production level of these immunoglobulins in examination at the early stages of the disease was established to be considerably lower than in the patients at the age from 7 to 12 months, and was equal to 1,1 ± 0,4 and 1,5 ± 0,1 U/ml versus 9,1 ± 3,8 U/ml correspondingly, (p