Power spectra density and similarity analysis of COVID-19 mortality waves across countries

Abstract

AbstractJohns Hopkins University CSSE documented waves of oscillatory COVID-19 mortality patterns worldwide during the COVID-19 pandemic. Here, we calculated the power spectrum density (PSD) of these COVID-19 mortality waves in 199 countries from January 22, 2020, to March 9, 2023. We identified two dominant peaks in the grand averaged PSD: one at a frequency of 1.15 waves per year (i.e., one wave every 10.4 months) and another at 2.7 waves per year (i.e., one wave every 4.4 months). Moreover, we performed a cosine similarity analysis of these PSD patterns among all the countries. The results showed a cosine similarity index distribution that was negatively skewed, with a skewness of −0.54 and a global median of cosine similarity index of 0.84, thus revealing a remarkable similarity in the dominant peaks of the COVID-19 mortality waves. These findings could be helpful if a future pandemic of a similar scale occurs so that effective confinement measures or other actions could be planned during these two identified periods, ensuring more assertive public health policies in advance.