Detectability of the novel coronavirus (SARS CoV 2) infection and rates of mortality for COVID 19 in different regions of the Russian Federation

Relevance Laboratory diagnosis of the novel coronavirus (SARS-CoV-2) infection combined with tracing/quarantine for contacts of infected individuals affects the spread of the SARS-CoV-2 infection and levels of related mortality. At the same time, testing practices for SARS-CoV-2 infection vary in the different regions of the Russian Federation. For example, in the city of St. Petersburg, where mortality rate for COVID-19 is the highest in the Russian Federation on Oct. 25, 2020, every death for COVID-19 corresponds to 15.7 detected cases of COVID-19 in the population, while the corresponding number for the whole of Russia is 58.1, suggesting limited detection of mild and moderate cases of COVID-19 in St. Petersburg. Additionally, while in some regions in Russia, all individuals with respiratory symptoms presenting for medical care are tested for SARS-CoV-2 infection, in a number of other regions in Russia, only certain categories of individuals presenting for medical care with respiratory symptoms were tested for the SARS-CoV-2 infection prior to Oct. 26, 2020. Materials & Methods More active testing for SARS-CoV-2 in the population results in increased detectability (i.e. the proportion of detected COVID-19 cases among all cases of SARS-CoV-2 infection in the population) and decreased case-fatality ratio (CFR, the proportion of deaths among reported COVID-19 cases in the population) – this because under more active testing, the number of mild and moderate cases of COVID-19 increases. We used data from the Russian Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor) on the number of detected cases and the number of deaths from COVID-19 in the different regions of the Russian Federation to examine the correlation between case-fatality ratios and rates of mortality for COVID-19 in different regions of the Russian Federation. Results The correlation between case-fatality ratios and rates of mortality for COVID-19 in the 85 different regions of the Russian Federation on Oct. 25, 2020 is 0.64 (0.50,0.75). For several regions of the Russian Federation, detectability of SARS-CoV-2 infection is relatively low, while rates of mortality for COVID-19 are relatively high. Conclusions Detectability of the SARS-CoV-2 infection is one of the factors that affects the levels of mortality from COVID-19 – higher detectability contributes to lower rates of mortality for COVID-19. To increase detectability, one ought to test all individuals with respiratory symptoms seeking medical care for SARS-CoV-2 infection (which is also suggested by the recent recommendations from the Ministry of Health), and to undertake additional measures to increase the volume of testing for SARS-CoV-2. Such measures, in combination with quarantine for infected cases and their close contacts help to mitigate the spread of the SARS-CoV-2 infection and diminish the related mortality. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work involves no funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: We used publicly available, aggregate data, with no informed consent from the participants sought, and no IRB approval required. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data used in this analysis are publicly available thorugh the following URLs in ref. 3,4: https://yandex.ru/maps/covid19?ll=87.127143%2C49.616265&z=3 https://showdata.gks.ru/report/278928/