key: cord-296593-ox6x53vj authors: Sonoo, M.; Idogawa, M.; Kanbayashi, T.; Shimohata, T.; Hayashi, H. title: Correlation between PCR Examination Rate among the Population and the Containment of Pandemic of COVID-19 date: 2020-05-16 journal: nan DOI: 10.1101/2020.05.13.20100982 sha: doc_id: 296593 cord_uid: ox6x53vj We investigated the relation between PCR examination rate among population and the success of containment of COVID-19. Although there was moderate negative correlation, the effect cannot be separated from that of Gross Domestic Product per capita (GDP), which may well be related to the strict compliance to social distancing. Close inspection of individual countries suggested that the social distancing is the largest factor to achieve containment, and the contribution of broad PCR tests is smaller. We investigated the relation between PCR examination rate among population and the success of containment of COVID-19. Although there was moderate negative correlation, the effect cannot be separated from that of Gross Domestic Product per capita (GDP), which may well be related to the strict compliance to social distancing. Close inspection of individual countries suggested that the social distancing is the largest factor to achieve containment, and the contribution of broad PCR tests is smaller. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 16, 2020. . https://doi.org/10.1101/2020.05.13.20100982 doi: medRxiv preprint Coronavirus disease 2019 (COVID-19) pandemic is now a worldwide peril and its control is an emergent issue. Expansion of PCR tests is generally believed to be the most important key for containing the infection, 1 together with social distancing. However, the relation between examination rate and the success of containment has not been directly studied. We investigated this issue based on the recent paper in Clinical Infectious Diseases. 2 The rate of PCR tests among population (Examination Rate; ER) was extracted from a website for countries having more than 1000 cases. 3 To evaluate the success of containment, the latest value of the new cases per 1 million population during 7 days in the trajectory analysis 2,4 was divided by its highest value, and was named as the Containment Ratio (CR). We postulated that strict compliance to social distancing is better achieved in advanced countries, and therefore Gross Domestic Product per capita (hereafter GDP) of each country was adopted as another predictor variable. The correlation between CR and ER/GDP was investigated by simple and multiple regressions/correlations using Microsoft Excel for Mac. Included were 84 countries. Individual countries are plotted in Figure 1 using logarithmic scales for every parameter. Notable countries are marked. As results, CR was negatively correlated both with ER (r = -0.445, p < 0.00001) and GDP (r = -0.441, p < 0.00001). In multiple regression, p-values of partial regression coefficients were 0.083 for ER and 0.102 for GDP, both insignificant. Accordingly, CR was indeed negatively correlated with ER, but we could not determine whether the main factor is ER or GDP, especially because ER and GDP were highly correlated (r = 0.752). Close inspection of individual countries reveals several interesting facts. Countries with the three highest ER are Iceland, UAE, and Bahrain. Iceland achieved world best containment, but in UAE and Bahrain the pandemic is not at all controlled. This may be related to large population of foreign workers in these countries. Three South-East Asian countries, Thailand, Malaysia and Singapore having similar climate and economical states (blue marks in Figure) All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 16, 2020. . https://doi.org/10.1101/2020.05.13.20100982 doi: medRxiv preprint 4 show a "positive" correlation, i.e. opposite to the general tendency. Singapore achieved very high ER (3.0%) among Asian countries but CR remains high. This may be related to the fact that Singapore government discouraged healthy peoples to wear a mask until early April. 5 However, this strategy may not have been so bad since attenuation of virulence is reported in Singapore, 6 and our analysis predicted the lowest Infection Fatal Rate (0.005%) in the world in Singapore (unpublished observation). The good result of Thailand may be due to prompt and intensive preventive measures including lock-down. 7 Japan is criticized by its very low ER (0.17%), 8 but major western countries generally achieving 2 to 5% ER may show better (Austria, Spain, Germany), similar (Italy, France, and Belgium) or worse (UK, Sweden, and USA) containment than Japan. These results imply that the social distancing is probably the largest factor to achieve containment, and the contribution of broad PCR tests is smaller. Funding: None reported. We would like to thank Dr. Katsuhisa Ogata, Department of Neurology, Higashisaitama National Hospital for the information on world countries. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted May 16, 2020. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. Diagnostic Testing for Severe Acute Respiratory Syndrome-Related Coronavirus-2: A Narrative Review Interactive web-based graphs of novel coronavirus COVID-19 cases and deaths per population by country. Clinical Infectious Diseases in press Reported Cases and Deaths by Country, Territory, or Conveyance Trajectory analysis of new coronavirus COVID-19 cases and deaths by country Coronavirus: Singapore Govt will no longer discourage wearing of masks, to give reusable masks to all households Discovery of a 382-nt deletion during the early evolution of SARS-CoV-2. bioRxiv preprint 2020 Coronavirus in Thailand: dealing with the 2019-nCoV (COVID-19) outbreak and impact Global Comparison of Changes in the Number of Test-Positive Cases and Deaths by Coronavirus Infection All rights reserved. No reuse allowed without permission.(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint this version posted May 16, 2020. . https://doi.org/10.1101/2020.05.13.20100982 doi: medRxiv preprint