[Epidemiological profile of pertussis in Rio Grande do Sul State, Brazil: a study of the correlation between incidence and vaccine coverage].

An upward trend was observed in pertussis incidence in the State of Rio Grande do Sul, Brazil, since 2000, leading to an epidemic alert in 2004, based on epidemiological bulletins issued by government health agencies. Our objective in the current study was to identify the epidemiological profile of pertussis in the State. We used the incidence of reports of the disease from January 1995 to December 2004, the percentage of vaccine coverage, and characterization of the affected population. A control diagram was constructed to determine the magnitude of the disease in 2004. To analyze the correlation between incidence and vaccine coverage, we established the fluctuation between the vaccine coverage and case reporting in the last ten years. In Rio Grande do Sul, pertussis was on an epidemic level in 2004, representing an important cause of morbidity and mortality in infants (< l year), despite the availability of effective vaccines and high vaccine coverage rates in recent years. Studies are thus needed on the disease pattern in the coming years in order to determine the factors involved in this resurgence.