{'fraction_non_alphanumeric': 0.04028331119964586, 'fraction_numerical': 0.04869411243913236, 'mean_word_length': 4.7215189873417724, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Towards the global equilibrium of COVID-19: statistical analysis of country-level data

Objectives: In our study, we explore the COVID-19 dynamics to test whether the virus has reached its equilibrium point and to identify the main factors explaining R and CFR variability across countries. Design: A retrospective study of publicly available country-level data. Setting: Fifty countries having the highest number of confirmed COVID--19 cases at the end of July 2021. Participants: Aggregated data including 182 085 182 COVID-19 cases confirmed in the selected fifty countries from the start of the epidemic to July 31, 2021. Primary and secondary outcome measures: The daily values of COVID-19 R and CFR measures were estimated using country-level data from the Our World in Data website. Results: The mean values of country-level moving averages of R and CFR went down from 1.114 and 5.51%, respectively, on July 31, 2020, to 1.059 and 2.35% on January 31, 2021, and to 1.010 and 2.17% by July 31, 2021. In parallel, the cross-country variance of R and CFR moving averages decreased from 0.015 and 0.19%, respectively, on July 31, 2020, to 0.004 and 0.02% on January 31, 2021, and stayed on a similar level by July 31, 2021. Conclusions: The continuous decrease in the country-level moving averages of R, down to the level of 1.0, accompanied by repeated outbreaks ("waves") in various countries, may indicate that COVID-19 has reached its point of a stable endemic equilibrium. Only a prohibitively high level of herd immunity (about 70%) can stop the endemic by reaching a stable disease-free equilibrium. Also, the average percentage of the fully vaccinated population appears to be the only statistically significant factor associated with country-specific CFR, bringing it close to the level of seasonal flu (about 0.1%) after vaccinating more than half of a country's population. Thus, while the currently available vaccines prove to be effective in reducing mortality from the existing COVID-19 variants, they are unlikely to stop the spread of the virus in the foreseeable future. It is noteworthy that no statistically significant effects of government measures restricting the people's behavior (such as lockdowns) were found in the analyzed data.