Temporal trends and spatial clusters of high risk for maternal death due to COVID-19 pre and during COVID-19 vaccination in Brazil: a national population-based ecological study.

OBJECTIVE: This study comprehensively analyzed the temporal and spatial dynamics of COVID-19 cases and deaths within the obstetric population in Brazil, comparing the periods before and during mass COVID-19 vaccination. We explored the trends and geographical patterns of COVID-19 cases and maternal deaths over time. We also examined their correlation with the SARS-CoV-2 variant circulating and the social determinants of health. STUDY DESIGN: This is a nationwide population-based ecological study. METHODS: We obtained data on COVID-19 cases, deaths, socioeconomic status, and vulnerability information for Brazil's 5570 municipalities for both the pre-COVID-19 vaccination and COVID-19 vaccination periods. A Bayesian model was used to mitigate indicator fluctuations. The spatial correlation of maternal cases and fatalities with socioeconomic and vulnerability indicators was assessed using bivariate Moran. RESULTS: From March 2020 to June 2023, a total of 23,823 cases and 1991 maternal fatalities were recorded among pregnant and postpartum women. The temporal trends in maternal incidence and mortality rates fluctuated over the study period, largely influenced by widespread COVID-19 vaccination and the dominant SARS-CoV-2 variant. There was a significant reduction in maternal mortality due to COVID-19 following the introduction of vaccination. The geographical distribution of COVID-19 cases and maternal deaths exhibited marked heterogeneity in both periods, with distinct spatial clusters predominantly observed in the North, Northeast, and Central West regions. Municipalities with the highest Human Development Index reported the highest incidence rates, while those with the highest levels of social vulnerability exhibited elevated mortality and fatality rates. CONCLUSION: Despite the circulation of highly transmissible variants of concern, maternal mortality due to COVID-19 was significantly reduced following the mass vaccination. There was a heterogeneous distribution of cases and fatalities in both periods (before and during mass vaccination). Smaller municipalities and those grappling with social vulnerability issues experienced the highest rates of maternal mortality and fatalities.