Recent findings on pertussis epidemiology in Turkey

The World Health Organization (WHO) reports that pertussis remains one of the least well-controlled vaccine-preventable diseases. It is supposed that the incidence of reported pertussis among adolescents, adults, and young infants has increased over the past decade. The aim of this study is to evaluate recent epidemiological data on pertussis in Turkey by regions. Data on vaccination coverage and pertussis incidence between 1986 and 2005 obtained from the Expanded Programme on Immunization national surveillance database of the Ministry of Health of Turkey were analyzed. Age and geographical distribution of the reported cases between 2000 and 2005 were evaluated. It was found that third-dose vaccination coverage increased from 1986 (45%) to 2005 (90%). In 2005, pertussis incidence tended to decrease (0.38 per 100,000) compared to 1986 (2.03 per 100,000). Even though only up to 6.5% of the cases were > or =15 years of age until 2005, 16.9% of them were included in this age group in 2005. It was observed that vaccination coverage rates steadily increased and pertussis incidence decreased by years despite some regional differences. In Turkey, pertussis incidence appears to be reaching the WHO targets, except East Anatolia. It is possible that waning immunity is responsible for the change of the age distribution of pertussis cases. However, priority should be given to strengthening available vaccination efforts throughout the country. A booster dose of pertussis vaccine in adolescence might be required in the future.