INTRODUCTION:
Measles is a highly transmissible viral disease of major public health relevance, with the potential to cause severe complications, particularly among children under five years of age. This study aimed to analyze the impact of vaccination coverage on the evolution of measles incidence and case fatality in the state of Bahia, Brazil, from 1980 to 2024.

METHODS:
A time-series study was conducted using confirmed measles cases and deaths among residents of the state of Bahia between 1980 and 2024. The number of cases, incidence rates per 100,000 inhabitants, number of deaths, case fatality rates, and vaccination coverage for measles were described based on records from the Notifiable Diseases Information System, the Mortality Information System, and the National Immunization Program Information System, respectively.

RESULTS:
During the 1980s, low measles vaccination coverage (ranging from 21% to 71%) was observed, accompanied by high incidence (213.4 cases per 100,000 inhabitants in 1986) and elevated case fatality (2.5% in 1980). In the 1990s, vaccination coverage expanded (up to 98%), resulting in reduced measles morbidity and mortality, although an outbreak occurred in 1999, when case fatality reached 7.1%. Between 2001 and 2014, sustained high vaccination coverage exceeding 100% led to the interruption of autochthonous transmission. Measles elimination certification was granted in 2016 by the Pan American Health Organization, but declining vaccination coverage after 2015 facilitated viral reintroduction in 2018 and the loss of elimination status in 2019. Recent outbreaks predominantly affected young adults, with greater vulnerability observed among individuals of mixed race.

CONCLUSIONS:
The control and subsequent elimination of measles in Bahia highlight the decisive role of vaccination. Sustaining high vaccination coverage and continuously strengthening the Unified Health System and the National Immunization Program are strategic measures to prevent future outbreaks.