The Difference in Wave Dynamics between SARS-CoV-2 Pre-Omicron and Omicron Variant Waves

Compared to previous SARS-CoV-2 variants, the Omicron variant exhibited different epidemiological features. The purpose of this study was to assess the wave dynamics of pre-Omicron and Omicron waves in terms of differences and similarities. We investigated the COVID-19 waves since the beginning of the pandemic up to 28 August 2022, 1000 waves in total, as to their effectiveness for flattening the curve, calculated from the first and second time derivative of the daily case data. The average number of Omicron waves per month (42.78) was greater than the one of pre-Omicron waves per month (25.62). Omicron waves steepen and flatten the curve significantly faster, more effectively and with sharper peaks. Omicron waves generated more daily case data than pre-Omicron waves; the pre-Omicron trend showed increasing numbers over time, whereas the Omicron trend showed decreasing numbers. In denser populated countries, pre-Omicron waves were managed more effectively, in contrast to Omicron waves which were managed less effectively (but more effectively in less densely populated countries). This study provides the evidence for a different behaviour of Omicron waves in terms of wave dynamics, and thereby confirms that the Omicron variant is not only genetically different but even more so in terms of epidemiological dynamics.