SARS-CoV-2/COVID-19 has affected millions of people worldwide. The trend of coronavirus disease 2019 (COVID-19) cases is not similar across countries, with several countries experiencing a decrease in the daily reported cases and deaths, while several others are reporting a surge in the daily reported cases and deaths. Bukhari, et al. (2020) acknowledge that studies of prior epidemics have suggested oscillatory patterns and cyclicity when analyzing long-term (ie, decades) epidemiological data; however, the researchers say to their knowledge, high-frequency oscillations (ie, weekly) have not been reported during prior epidemics. In this cross-sectional study, the researchers investigate oscillatory patterns in COVID-19 cases and deaths.
Bukhari, et al. (2020) explain that this study was not submitted for institutional review board approval and informed consent was not sought because it uses publicly available data at the population level, in accordance with 45 CFR §46.
The researchers identified oscillatory patterns in the daily reported new cases and deaths with a periodicity of approximately 1 week for the US, Germany, Canada, Italy, Brazil, and the United Kingdom. The data from Germany and Italy show dampened oscillations (decreasing amplitude with time) for both newly reported infections and deaths, with a −92% change in peak-to-peak oscillatory pattern in the daily reported deaths in Germany between April and July 2020, which might indicate a substantial decay in the spread of the virus. However, the data from the US and Brazil show no sign of dampening, with a −43% change in peak-to-peak oscillatory pattern in the daily reported deaths in the U.S. between April and July 2020, which suggests that the U.S. and Brazil are still not at the decaying phase. The spectral density plot in panel B of the Figure confirms an oscillatory pattern of 7 days. The rose plot in panel C of the Figure shows the polar histogram of the phase angle difference between daily new cases and deaths and demonstrates a lag between daily new cases and deaths of 2 days for the U.S. and 1 day for Germany. However, this lag is not due to the epidemiology of the disease but possibly is associated with bias in the surveillance system.
Reference: Bukhari Q, et al. Periodic Oscillations in Daily Reported Infections and Deaths for Coronavirus Disease 2019. JAMA Netw Open. 2020;3(8):e2017521. doi:10.1001/jamanetworkopen.2020.17521