Introduction: In 2009, the World Health Organization reported a new
pandemic. In Brazil, almost 90,000 cases of severe acute respiratory
syndrome were confirmed. This study aims to investigate the factors
associated with the 2009 pandemic influenza rate in Brazilian capitals.
Methods: Ecological study, in which data were collected from the
government information system. Thematic maps were built to describe the
rate by sex and age group. Chi-square tests were used to evaluate the
association between pandemic influenza incidence and the following
factors: age group, sex, climate, Gross Domestic Product per capita, and
region. The adjusted rate ratio of influenza was estimated using the
multilevel Poisson model. Fixed effects were age group, sex, climate,
GDP, and interaction terms. Random effects were capital (intercept) and
region (slope). Results: A total of 13,171 confirmed cases of pandemic
influenza were reported in 2009, in which 56% occurred in women, 39%
in the 20-39 years age group, and 43% in the Southeast. The 2009 global
rate of pandemic influenza in Brazilian capitals was 35.70/100,000.
Women, 20-39 years of age group and subtropical climate showed the
highest risk of getting ill. The highest and the lowest rates of
pandemic influenza were observed in capitals of the South and Northeast
regions, respectively. Conclusions: The 2009 pandemic influenza evidence
high risk in adults and adolescents, female and subtropical climate.
Continued social and health interventions to prevent and tackle
influenza outbreaks and a robust surveillance information system are
necessary to effectively control the disease.