The Ongoing COVID-19 Epidemic Curves Indicate an Initial Point Spread in China with Log-Normal Distribution of New Cases Per Day, with A Predictable Last Date of The Outbreak Version 4: Predictions for Selected European Countries, USA, and The World as A Whole, and Try to Predict The End of The Outbreak, Including A Discussion of A Possible “New Normal”

Author(s): Stefan Olsson and Jing Zhang

During an epidemic outbreak, it is useful for planners and responsible authorities to be able to plan to estimate when an outbreak of an epidemic is likely to ease and when the last case can be predicted in their area of responsibility. Theoretically, this could be done for a point source epidemic using epidemic curve forecasting. The extensive data now coming out of China makes it possible to test if this can be done using MS Excel, a standard spreadsheet program available in most offices. The available data is divided up for China as a whole and the different provinces. This and the high number of cases, and the daily updates made the analysis possible. Data for new confirmed infections for Hubei, Hubei outside Wuhan, China, excluding Hubei as well as Zhejiang and Fujian provinces, all follow a log-normal distribution that can be used to make a rough estimate for the date of the last new confirmed cases in respective areas (v1 published at bioRxiv. In the v2 (bioRxiv) continuation work, 9 additional days were added for the Chinese data to evaluate the previous predictions, supporting the usefulness of the simple technique and testing the feasibility for a non-specialist to make similar predictions using data from South Korea, then available. In v2, the predictions for V2 were evaluated for South Korea and fit well with the beginning of the decline, but in South Korea, it seemed to be difficult to go below 100 new cases per day; potential reasons for this are discussed. To further evaluate when a prediction becomes reliable, the Chinese data was used to evaluate making predictions for each day around the peak in the number of cases to pinpoint when a prediction of the end of a point outbreak is reliable, and that is after2-3 consecutive days of decreasing new cases per day. In v3 (bioRxiv), data for Italy were used to make further predictions for that country. A second new analysis was added to use the fitted equation to detect when the acceleration of new cases per day stopped increasing exponentially. In China, this measured point coincides with the date of the complete Hubei lockdown, and in the new Italian analysis, it coincides with the mandatory Italian lockdown. In this version, v4 (bioRxiv), we expand the analysis to selected European countries, the USA, and the World as a whole. Now, 5 years later, we further discuss the apparent success of the used techniques that might work as a “new normal” with a preparedness to stop secondary outbreaks of COVID-19, as well as to better counteract future COVIDs that are sure to come in an interconnected world with fast travel between countries and between large population centres.