Aglomeração espacial e heterogeneidade do excesso de morbidade e mortalidade da pandemia da COVID-19 em duas capitais brasileiras durante as ondas epidêmicas do período de 2020 a 2022

Abstract

The analysis of COVID-19 transmission dynamics is an important tool for understanding the disease, monitoring cases, and preventing future waves. This thesis aimed to detect epidemic waves and spatial clusters, and to investigate the spatial heterogeneity of excess morbidity and mortality in two Brazilian capitals, Rio de Janeiro and Salvador, from 2020 to 2022. Three ecological studies were carried out: one of time series to detect epidemic waves of cases and deaths by COVID-19, using an algorithm based on parameters defined with biological information on disease transmission translated into mathematical rules; one of area data to investigate spatial clusters of incidence and mortality by COVID-19, using three spatial analysis techniques; and one of area data to investigate excess morbidity and mortality by COVID-19, through the analysis of the standardized morbidity and mortality ratio - the last two considering the waves identified in the first study. Six epidemic waves of cases were identified in Rio de Janeiro (two in 2020, one in 2021, and three in 2022), lasting between 113 and 313 days, and five waves of deaths (one in 2020, two in 2021, and two in 2022), lasting between 137 and 304 days. Salvador had five waves of cases (one in 2020, one in 2021, and three in 2022), lasting between 124 and 415 days, and three waves of deaths, one in each year, lasting between 247 and 425 days. There was one main morbidity cluster and one mortality cluster in Rio de Janeiro, and three morbidity clusters in Salvador, in addition to smaller “secondary” clusters. Excess morbidity and mortality from COVID-19 were also identified in a minority of neighborhoods, both in Rio de Janeiro and Salvador, in addition to great local heterogeneity of the excess in both cities. The epidemic waves identified differ in number and duration from those described in epidemiological reports. These detected waves are consistent with the emergence of variants and the adoption of non-pharmacological coping measures and vaccination during the pandemic. The regions most affected by excess morbidity from COVID-19, as well as the occurrence of spatial clusters, are also those with the highest level of connectivity, suggesting that the flow of people may be related to greater transmission of the disease. In this sense, planning of COVID-19 control and intervention measures should preferably address these locations.