Abstract
The incidence data were obtained from the following information sources: archives of the National Institute of Public Health for the period up to 1964, archives of the Institute of Health Information and Statistics for 1965-1981, Communicable Disease Information System for 1982-1992 and Communicable Disease Notification System EPIDAT for 1992-2008. The mortality data were obtained, apart from the aforementioned sources, also from the literature.
The case definition was based on that provided by the Bulletin of the Ministry of Health and the EC Directive. Cases were notified in accordance with the guidelines of the respective information systems and the principles of pertussis surveillance laid down by the regulations.
An epidemiological investigation form was filled in for each case of pertussis, indicating the type of laboratory analysis. The methods used for laboratory diagnosis of pertussis were culture, serology and a PCR assay