Identification of COVID-19 mortality patterns in Brazil by a functional QR decomposition analysis

TL;DR

This paper uses a functional QR decomposition method to identify independent COVID-19 mortality patterns in Brazil, revealing key regional differences and two main epidemic curves with distinct peaks and shifts.

Contribution

It introduces a novel application of functional QR decomposition for analyzing COVID-19 mortality data to uncover independent regional patterns.

Findings

Identified two main independent COVID-19 mortality curves with two peaks each.

Mapped two primary epidemiological regions in Brazil based on mortality patterns.

Demonstrated the effectiveness of functional QR decomposition in epidemiological data analysis.

Abstract

The subset selection problem of linear algebra is applied to identify independent patterns of COVID-19 evolution within Brazil. The data consist of a set of mortality curves in states of Brazil. A subset of the most independent curves is selected by using a functional version of the QR matrix decomposition technique with column pivoting. The selected subset is used next as a basis to represent the remaining curves filtering out any data redundancy. For each independent curve, an associated epidemiological region of influence is defined. The results show two main independent curves with a similar two-peak pattern and a 50-day shift between the patterns. Two main epidemiological regions are next identified: one encompassing most of the country from the center and northeast states to the south, an another one containing the Amazonian region at the northwest.