Pertussis is an acute anthroponous infection that occurs with damage to the respiratory tract and it causes attacks of spastic cough. Despite specific prevention, it remains an important cause of childhood illness and mortality. The article analyzes the literature data on the mechanisms of infection pathogenesis, highlights aspects of immunization and the work of the immune system after the introduction of pertussis vaccine. Examples of own observations of children diagnosed with pertussis are given. It was concluded that vaccination does not guarantee the full-fledged immune response and the risk of pertussis infection remains even in vaccinated children, but in such cases, the infection proceeds in an atypical form. At the same time, a child unvaccinated with the anti-pertussis vaccine has a higher risk of contracting the infection with a prolonged course and the possibility of developing complications from the respiratory, cardiovascular and nervous systems.