abstract: 'Background COVID-19 spread rapidly in Brazil despite the country''s well established health and social protection systems. Understanding the relationships between health-system preparedness, responses to COVID-19, and the pattern of spread of the epidemic is particularly important in a country marked by wide inequalities in socioeconomic characteristics (eg, housing and employment status) and other health risks (age structure and burden of chronic disease). Methods From several publicly available sources in Brazil, we obtained data on health risk factors for severe COVID-19 (proportion of the population with chronic disease and proportion aged >= 60 years), socioeconomic vulnerability (proportions of the population with housing vulnerability or without formal work), health-system capacity (numbers of intensive care unit beds and physicians), coverage of health and social assistance, deaths from COVID-19, and state-level responses of government in terms of physical distancing policies. We also obtained data on the proportion of the population staying at home, based on locational data, as a measure of physical distancing adherence. We developed a socioeconomic vulnerability index (SVI) based on household characteristics and the Human Development Index. Data were analysed at the state and municipal levels. Descriptive statistics and correlations between state-level indicators were used to characterise the relationship between the availability of health-care resources and socioeconomic characteristics and the spread of the epidemic and the response of governments and populations in terms of new investments, legislation, and physical distancing. We used linear regressions on a municipality-by-month dataset from February to October, 2020, to characterise the dynamics of COVID-19 deaths and response to the epidemic across municipalities. Findings The initial spread of COVID-19 was mostly affected by patterns of socioeconomic vulnerability as measured by the SVI rather than population age structure and prevalence of health risk factors. The states with a high (greater than median) SVI were able to expand hospital capacity, to enact stringent COVID-19-related legislation, and to increase physical distancing adherence in the population, although not sufficiently to prevent higher COVID-19 mortality during the initial phase of the epidemic compared with states with a low SVI. Death rates accelerated until June, 2020, particularly in municipalities with the highest socioeconomic vulnerability. Throughout the following months, however, differences in policy response converged in municipalities with lower and higher SVIs, while physical distancing remained relatively higher and death rates became relatively lower in the municipalities with the highest SVIs compared with those with lower SVIs. Interpretation In Brazil, existing socioeconomic inequalities, rather than age, health status, and other risk factors for COVID-19, have affected the course of the epidemic, with a disproportionate adverse burden on states and municipalities with high socioeconomic vulnerability. Local government responses and population behaviour in the states and municipalities with higher socioeconomic vulnerability have helped to contain the effects of the epidemic. Targeted policies and actions are needed to protect those with the greatest socioeconomic vulnerability. This experience could be relevant in other low-income and middle-income countries where socioeconomic vulnerability varies greatly.Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.' affiliation: 'Atun, R (Corresponding Author), Harvard TH Chan Sch Publ Hlth, Dept Global Hlth \& Populat, Boston, MA 02115 USA. Rocha, Rudi; Massuda, Adriano, Fundacao Getulio Vargas, Sao Paulo Sch Business Adm, Sao Paulo, Brazil. Rocha, Rudi; Rache, Beatriz; Nunes, Leticia, Inst Estudos Polit Saude, Sao Paulo, Brazil. Atun, Rifat; Castro, Marcia C., Harvard TH Chan Sch Publ Hlth, Dept Global Hlth \& Populat, Boston, MA 02115 USA. Spinola, Paula, UCL, Ctr Global Hlth Econ, London, England. Lago, Miguel, Inst Estudos Polit Saude, Rio De Janeiro, Brazil.' author: Rocha, Rudi and Atun, Rifat and Massuda, Adriano and Rache, Beatriz and Spinola, Paula and Nunes, Leticia and Lago, Miguel and Castro, Marcia C. author-email: ratun@hsph.harvard.edu author_list: - family: Rocha given: Rudi - family: Atun given: Rifat - family: Massuda given: Adriano - family: Rache given: Beatriz - family: Spinola given: Paula - family: Nunes given: Leticia - family: Lago given: Miguel - family: Castro given: Marcia C. da: '2023-09-28' doi: 10.1016/S2214-109X(21)00081-4 earlyaccessdate: MAY 2021 esi-highly-cited-paper: Y esi-hot-paper: N files: [] issn: 2214-109X journal: LANCET GLOBAL HEALTH keywords-plus: COMMUNICATION language: English month: JUN number: '6' number-of-cited-references: '38' orcid-numbers: 'Spinola, Paula/0000-0002-4554-4250 Castro, Marcia/0000-0003-4606-2795' pages: E782-E792 papis_id: 226fc75d3a4c55779118d4e972112da8 ref: Rocha2021effectsocioeconomic researcherid-numbers: 'Spinola, Paula/HKW-4879-2023 Castro, Marcia/S-2681-2019' times-cited: '131' title: 'Effect of socioeconomic inequalities and vulnerabilities on health-system preparedness and response to COVID-19 in Brazil: a comprehensive analysis' type: article unique-id: WOS:000652845500025 usage-count-last-180-days: '5' usage-count-since-2013: '35' volume: '9' web-of-science-categories: Public, Environmental \& Occupational Health year: '2021'