OBJECTIVE: The objective of this study was to evaluate the impact of influenza vaccination on hospital admissions and deaths from respiratory and circulatory diseases in the city of Fortaleza, located in the state of Ceará, Brazil. METHODS: Brazilian Health Ministry data regarding deaths from respiratory and circulatory diseases occurring between 1995 and 2001, as well as hospital admissions related to such diseases between 1995 among 2003, in both cases limited to residents of Fortaleza above the age of 60 years, were analyzed. RESULTS: There were 29,867 admissions for respiratory disease. Between 1995 and 1998, the mean number of annual admissions was 3067.3 (standard deviation, 365.8). Between 1999 and 2003, the average was 3519 (standard deviation, 195.6). When adjusted for the increase in population, the difference between the two periods was less than significant. From 1998 to 1999, there was no significant reduction in the number of admissions from circulatory disease (p > 0.641). Nor was there a significant reduction from 1998 to 2000 (p < 0.5) or from 1998 to 2003 (p > 0.72), although there were significant reductions in 2000 (p < 0.002) and 2001 (p < 0.0014). There was a significant reduction in the number of deaths and in overall mortality rates during 1999, 2000 and 2001 in relation to 1998 (p < 0.05), with no difference between 2000 and 2001. The monthly distribution of admissions was not altered as a result of the vaccinations. CONCLUSION: Our data show that vaccination of the elderly did not achieve the desired results. This suggests that seasonality studies are needed in order to identify the ideal time of year for such vaccinations.
Influenza; Vaccination; Respiratory tract infection; Death certificates; Length of stay
