Influenza in Brazilian macroregions: an analysis of temporal trends in vaccination and mortality rates.

Abstract

Background: Influenza infection is a topic of debate in Brazil, as pronounced socioeconomic and healthcare disparities among its macro-regions may contribute to different epidemiological profiles. Aim: Evaluate temporal patterns in influenza mortality and vaccination in Brazil and its macro-regions. Methodology: This ecological study examined temporal patterns in influenza vaccination coverage and mortality rates from 1996 to 2022. Annual incidence, mortality, and vaccination rates per 100,000 inhabitants were assessed across the country's five macro-regions, using the annual percentage change (APC) to measure the observed trend. Results: Between 1996 and 1999, all Brazilian regions showed growth in influenza vaccination coverage (around 36% annually), followed by a significant decline until 2022 (around 3.6% annually). The Southeast maintained the best vaccination and mortality rates, while the North had the lowest. Mortality fluctuated cyclically, exhibiting complex trend patterns. It is worth noting the sustained growth of its rates in the North of 4.8% per year. The Midwest and South exhibited alternating periods of growth and stability. In general, the trends reflect consistent regional changes over time. Conclusions: Regional inequalities in vaccination and mortality in Brazil highlight inequities in access to healthcare and present challenges for public policy, necessitating targeted strategies to enhance vaccination coverage and reduce regional disparities.