PERSISTENCE AND CHANGES IN EMERGING COVID-19 SPACE-TIME CLUSTERS IN BRAZILIAN MUNICIPALITIES IN 2020-2021

Abstract

The impacts of COVID-19 in Brazil are evident and exacerbate the country´s inequalities. This study aimed to analyze the persistence and changes in the log-likelihood ratio (LLR), radius, duration, observed and expected number of cases, p-values, number of municipalities, population, and the relative risk of space-time clusters of COVID-19 cases identified in Brazilian municipalities in the epidemiological weeks with peak transmission in 2020 and 2021. The study period was from the epidemiological week (EW) 09-2020 to EW 29-2021 (23 February 2020 to 24 July 2021). The prospective space-time scan was performed during the EW with peaks in case numbers and repeated in the five subsequent EWs to verify clusters’ persistence and changes over space and time. COVID-19 clusters were identified in a large part of Brazil´s territory. Over the analyzed period, the clusters´ disposition patterns became increasingly similar, and the clusters were identified in akin locations. The detected clusters also became more persistent, with longer duration; and stronger, with higher LLR. The methodology identified areas with greater risk of COVID-19 that should be prioritized for better allocation of health resources to mitigate transmission.