Sars-Cov2 world pandemic recurrent waves controlled by variants evolution and vaccination campaign

While understanding the time evolution of Covid-19 pandemic is needed to plan economics and tune sanitary policies, a quantitative information of the recurrent epidemic waves is elusive. This work describes a statistical physics study of the subsequent waves in the epidemic spreading of Covid-19 and disclose the frequency components of the epidemic waves pattern over two years in United States, United Kingdom and Japan. These countries have been taken as representative cases of different containment policies such as Mitigation (USA and UK) and Zero Covid (Japan) policies. The supercritical phases in spreading have been identified by intervals with RIC-index> 0. We have used the wavelet transform of infection and fatality waves to get the spectral analysis showing a dominant component around 130 days. Data of the world dynamic clearly indicates also the crossover to a different phase due to the enforcement of vaccination campaign. In Japan and United Kingdom, we observed the emergence in the infection waves of a long period component (similar to 170 days) during vaccination campaign. These results indicate slowing down of the epidemic spreading dynamics due to the vaccination campaign. Finally, we find an intrinsic difference between infection and fatality waves pointing to a non-trivial variation of the lethality due to different gene variants.

Automated summary

This study uses statistical physics to study the epidemic waves of the Covid-19 pandemic. The results show that there are different frequency components in the epidemic waves in the United States, United Kingdom, and Japan over a two-year period. The study finds that the vaccination campaign slows down the spread of the epidemic, and there is an intrinsic difference between infection waves and fatality waves, possibly due to genetic variations.