Introduction and objective: Bordetella pertussis is a Gram-negative rod which attacks the respiratory system and causes whooping cough disease. Despite the high percentage of childhood vaccination amongst the population an increasing number of pertussis cases have been observed over time, especially among adolescents and young adults. Objective: The aim of the study was to analyze the concentration of IgG anti-PT Bordetella antibodies in the serum of young adults in the aspect of maintaining immunity. Material and methods: The study group consisted of 30 patients, medical students aged 21–26 years. They were interviewed with a questionnaire, which asked about their general health, medications taken, basic information about whooping cough, or vaccination status against B. pertussis. The anti-PT Bordetella levels were measured in the collected serum by a commercial ELISA kit (enzyme-linked immunosorbent assay). Results: All patients had previously received a mandatory vaccination for pertussis as a child, and 36.6%had received a booster dose after the age of 18. The total average antibody level was 13.977 IU/mL (range: <5.00 – 50.74) and 40% of samples had a very low concentration (<5 IU/mL). Conclusions: Current findings suggest that post-vaccine immunity decreases over time, while infection susceptibility among younger age groups who have not yet been fully immunized has increased. Methods that could prevent and enable risk stratification of whooping cough include the screening test for anti-PT Bordetella antibody, the improvement of diagnostics, and an additional booster dose.