1.Simonsen, L, et al. The impact of influenza epidemics on mortality: introducing a severity index. American Journal of Public Health 1997; 87: 1944–1950.
2.Simonsen, L, et al. Pandemic versus epidemic influenza mortality: a pattern of changing age distribution. Journal of Infectious Diseases 1998; 178: 53–60.
3.World Health Organization. Adoption of global agenda on influenza. Weekly Epidemiological Record 2002; 77: 191–195.
4.Bisno, AL, et al. Pneumonia and Hong Kong influenza: a prospective study of the 1968–69 epidemic. American Journal of the Medical Sciences 1971; 116: 51–53.
5.Gupta, RK, George, R, Nguyen-Van-Tam, JS. Bacterial pneumonia and pandemic influenza planning. Emerging Infectious Diseases 2008; 14: 1187–1192.
6.Nichol, KL, Baken, L, Nelson, A. Relation between influenza vaccination and outpatient visits, hospitalization, and mortality in elderly persons with chronic lung disease. Annals of Internal Medicine 1999; 130: 397–403.
7.Upshur, REG, Knight, K, Goel, V. Time-series analysis of the relation between influenza virus and hospital admissions of the elderly in Ontario, Canada, for pneumonia, chronic lung disease, and congestive heart failure. American Journal of Epidemiology 1999; 149: 85–92.
8.Griffin, MR, et al. Winter viruses: influenza and respiratory syncytial virus related morbidity in chronic lung disease. Archives of Internal Medicine 2002; 162: 1229–1236.
9.Alling, DW, Blackwelder, WC, Stuart-Harris, CH. A study of excess mortality during influenza epidemics in the United States, 1968–1976. American Journal of Epidemiology 1981; 113: 30–43.
10.Lui, KJ, Kendal, AP. Impact of influenza epidemics on mortality in the United States from October 1972 to May 1985. American Journal of Public Health 1987; 77: 712–716.
11.Reichert, T, et al. Influenza and the winter increase in mortality in the United States, 1959–1999. American Journal of Epidemiology 2004; 160: 492–502.
12.Thompson, WW, et al. Mortality associated with influenza and respiratory syncytial virus in the United States. Journal of the American Medical Association 2003; 289: 179–86.
13.Chow, A, et al. Influenza-associated deaths in tropical Singapore. Emerging Infectious Diseases 2006; 12: 114–121.
14.Wong, CM, et al. Influenza-associated mortality in Hong Kong. Clinical Infectious Diseases 2004; 39: 1611–1617.
15.Centers for Disease Control and Prevention. Estimates of deaths associated with seasonal influenza – United States, 1976–2007. Morbidity and Mortality Weekly Report 2010; 59: 1057–1062.
16.Viboud, C, Alonso, WJ, Simonsen, L. Influenza in tropical regions. PLoS Medicine 2006; 3: e89.
17.Moura, FEA. Influenza in the tropics. Current Opinion in Infectious Diseases 2010; 23: 415–420.
18.Carvalho, MTB, et al. The National Immunization Program in the 20 years of Unified Health System in Brazil. In: Health Brazil 2008: 20 years of Unified Health System (SUS) in Brazil. Brasilia: Ministry of Health, 2009, pp. 63–83.
19.Alonso, WJ, et al. Seasonality of influenza in Brazil: a traveling wave from the Amazon to the subtropics. American Journal of Epidemiology 2007; 165: 1434–1442.
20.Brazilian Institute of Geography and Statistics. Censo demografico 1980, 1990, 2000. (http://www.ibge.gov.br). Accessed 25 November 2010.
23.World Health Organization. Manual of the International Statistical Classification of Diseases, Injuries, and Causes of Death, Based on Recommendations of the Ninth Revision Conference, 1975. Geneva: World Health Organization; 1977.
24.World Health Organization. Manual of the International Statistical Classification of Diseases, Injuries, and Causes of Death, Based on Recommendations of the Tenth Revision Conference, 1992. Geneva: World Health Organization; 1992.
25.Serfling, RE. Methods for current statistical analysis of excess pneumonia-influenza deaths. Public Health Reports 1963; 78: 494–506.
26.Serfling, RE, Sherman, IL, Houseworth, WJ. Excess pneumonia-influenza mortality by age and sex in three major influenza A2 epidemics, United States, 1957–58, 1960 and 1963. American Journal of Epidemiology 1967; 86: 433–441.
28.Cohen, C, et al. Elevated influenza-related excess mortality in South African elderly individuals, 1998–2005. Clinical Infectious Diseases 2010; 51: 1362–1369.
29.The Macroepidemiology of Influenza Vaccination (MIV) Study Group. The macroepidemiology of influenza vaccination in 56 countries, 1997–2003. Vaccine 2005; 23: 5133–5143.
30.Antunes, JL, et al. Effectiveness of influenza vaccination and its impact on health inequalities. International Journal of Epidemiology 2007; 36: 1319–1326.
31.de Mello, WA, et al. The dilemma of influenza vaccine recommendations when applied to the tropics: the Brazilian case examined under alternative scenarios. PLoS One 2009; 4: e5095.
32.Thompson, WW, et al. Estimates of US influenza-associated deaths made using four different methods. Influenza and Other Respiratory Viruses 2009; 3: 37–49.
33.Newall, AT, Viboud, C, Wood, JG. Influenza-attributable mortality in Australians aged more than 50 years: a comparison of different modelling approaches. Epidemiology and Infection 2010; 138: 836–842.
34.Inter-Agency Health Information Network (RIPSA). Basic Indicators for Health in Brazil: Concepts and Applications, 2nd edn. Brasilia: Pan-American Health Organization, 2008, pp. 292–293.
35.Mello-Jorge, MHP, Gotlieb, SLD, Laurenti, R. The national mortality information system: problems and proposals for solving them. I – Deaths by natural causes. Revista Brasileira de Epidemiologia 2002; 5: 197–211.