Bordetella pertussis infection, known as pertussis or whooping cough, is one of the leading causes of vaccine- preventable deaths. Worldwide, an estimated 50 million cases of pertussis and 300 000 deaths occur every year, mainly in unvaccinated children younger than 12 months of age. B. pertussis infection in adults and adolescents usually causes mild or atypical symptoms. Pertussis should be considered in the differential diagnosis of illnesses with cough lasting more than 1–2 weeks. Pertussis may also cause infection in adults with comorbid conditions such as chronic obstructive pulmonary disease (COPD), and it is one of the less common causes of exacerbations of COPD. Pertussis shows a slight seasonality, with a usually modest increase in cases in the summer and autumn. The percentage of infants reaching their first birthday fully vaccinated against pertussis is shown in figure 2. Vaccination coverage is high throughout the EU28 countries.
Pertussis vaccination schedules vary between European countries, as do the indications for booster vaccination in adolescents and adults. These differences in approach are, at least in part, related to the varying incidence of pertussis in adolescents and adults in Europe. Data from EUVAC-NET show an increase in the number of reported cases in the EU and in European Economic Area (EEA)/European Free Trade Association (EFTA) countries between 2006 and 2009, from 3.75 to 4.89 per 100 000; the most affected group was 5–14-year-olds with a confirmed case rate slightly above 17 per 100 000.
The main problem in epidemiological analysis of the disease is the heterogeneity of pertussis surveillance, particularly in terms of the surveillance systems, coverage, laboratory methods used and case definition applied.