Epidemiology and Infection

Original Papers

Viruses

Influenza-associated excess mortality in southern Brazil, 1980–2008

F. T. M. FREITASa1 c1, L. R. O. SOUZAa1, E. AZZIZ-BAUMGARTNERa2, P. Y. CHENGa2, H. ZHOUa2, M. A. WIDDOWSONa2, D. K. SHAYa2, W. K. OLIVEIRAa1 and W. N. ARAUJOa1

a1 Health Surveillance Secretariat, Ministry of Health, Brasilia, Brazil

a2 Centers for Disease Control and Prevention, Atlanta, GA, USA

SUMMARY

In order to estimate influenza-associated excess mortality in southern Brazil, we applied Serfling regression models to monthly mortality data from 1980 to 2008 for pneumonia/influenza- and respiratory/circulatory-coded deaths for all ages and for those aged ≥60 years. According to viral data, 73·5% of influenza viruses were detected between April and August in southern Brazil. There was no clear influenza season for northern Brazil. In southern Brazil, influenza-associated excess mortality was 1·4/100 000 for all ages and 9·2/100 000 person-years for persons aged ≥60 years using underlying pneumonia/influenza-coded deaths and 10·0/100 000 for all ages and 86·6/100 000 person-years for persons aged ≥60 years using underlying respiratory/circulatory-coded deaths. Influenza-associated excess mortality rates for southern Brazil are similar to those published for other countries. Our data support the need for continued influenza surveillance to guide vaccination campaigns to age groups most affected by this virus in Brazil.

(Received February 05 2012)

(Revised August 04 2012)

(Accepted September 05 2012)

(Online publication October 08 2012)

Key words

  • Brazil;
  • epidemiology;
  • influenza

Correspondence

c1 Author for correspondance: Dr F. T. M. Freitas, Ministerio da Saude, Coordenação Geral de Doenças Transmissiveis, Unidade de Doenças Respiratorias e Imunopreviniveis, Setor Comercial Sul, Quadra 4, Bloco A, 2° andar, CEP: 70304-000, Brasilia-DF, Brazil. (Email: felipe.freitas@saude.gov.br)

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