Scaling law of COVID-19 cases and city size and its evolution over time

Urban scaling law quantifies the disproportional growth of urban indicators with urban population size, which is one of the simple rules behind the complex urban system. Infectious diseases are closely related to social interactions that intensify in large cities, resulting in a faster speed of transmission in large cities. However, how this scaling relationship varies in an evolving pandemic is rarely investigated and remains unclear. Here, taking the COVID- 19 epidemic in the United States as an example, we collected daily added cases and deaths from January 2020 to June 2022 in more than three thousand counties to explore the scaling law of COVID- 19 cases and city size and its evolution over time. Results show that COVID- 19 cases super- linearly scaled with population size, which means cases increased faster than population size from a small city to a large city, resulting in a higher morbidity rate of COVID- 19 in large cities. Temporally, the scaling exponent that reflects the scaling relationship stabilized at around 1.25 after a fast increase from less than one. The scaling exponent gradually decreased until it was close to one. In comparison, deaths caused by the epidemic did not show a super-linear scaling relationship with population size, which revealed that the fatality rate of COVID-19 in large cities was not higher than that in small or medium-sized cities. The scaling exponent of COVID- 19 deaths shared a similar trend with that of COVID- 19 cases but with a lag in time. We further estimated scaling exponents in each wave of the epidemic, respectively, which experienced the common evolution process of first rising, then stabilizing, and then decreasing. We also analyzed the evolution of scaling exponents over time from regional and provincial perspectives. The northeast, where New York State is located, had the highest scaling exponent, and the scaling exponent of COVID- 19 deaths was higher than that of COVID-19 cases, which indicates that large cities in this region were more prominently affected by the epidemic. This study reveals the size effect of infectious diseases based on the urban scaling law, and the evolution process of scaling exponents over time also promotes the understanding of the urban scaling law. The mechanism behind temporal variations of scaling exponents is worthy of further exploration. © 2023 Science Press. All rights reserved.

The RM Partners Cancer Hub approach to Upper Gastrointestinal Surgery during the COVID-19 pandemic

Background: The COVID-19 pandemic led to significant cancellations of major surgery to maximise critical care capacity. Our unit instituted the 'RM Partners Cancer Hub' based at the Royal Marsden Hospital in London, which allowed cancer surgery from multiple NHS Trusts to continue in a 'COVID-lite' setting. We present the outcomes for Upper GastroIntestinal (UGI) surgery managed via this approach over the course of the pandemic. Method(s): From April 2020 to April 2021, the Royal Marsden Hospital formed the 'RM Partners Cancer Hub'. This was designed to co-ordinate resources and deliver as much oncological treatment and cancer surgery as feasible for patients across the RM Partners West London Cancer Alliance. An UGI clinical case prioritisation strategy, along with strict infection control pathways and pre-operative screening protocols were adopted. Result(s): Overall, 231 patients underwent surgery for confirmed UGI cancer via the RM Partners Cancer Hub, with 213 completed resections and combined 90-day mortality rate of 3.5%. Good short-term survival outcomes were demonstrated with 2-year Disease Free Survival (DFS) and Overall Survival (OS) for oesophageal (DFS 70.8%;OS 72.9%), gastric (DFS 66.7%;OS 83.3%) and pancreatic cancer resections (DFS 68.0%, OS 88.0%). One patient developed peri-operative COVID-19 during the RM Partners Cancer Hub operation;they made a full recovery with no lasting clinical sequelae. Conclusion(s): The 'RM Partners Cancer Hub' approach provided a workable model for delivering multidisciplinary UGI cancer care and surgery with favourable 2-year DFS and OS when compared to nationally published pre- and post-pandemic data. It also established a template for cancer service during periods of marked disruption to healthcare service delivery and should be a useful guide in the future planning of safe operating pathways.

CoAvoid: Secure, Privacy-Preserved Tracing of Contacts for Infectious Diseases

To fight against infectious diseases (e.g., SARS, COVID-19, Ebola, etc.), government agencies, technology companies and health institutes have launched various contact tracing approaches to identify and notify the people exposed to infection sources. However, existing tracing approaches can lead to severe privacy and security concerns, thereby preventing their secure and widespread use among communities. To tackle these problems, this paper proposes CoAvoid, an edge-based, privacy-preserved contact tracing system that features good dependability and usability. CoAvoid leverages the Google/Apple Exposure Notification (GAEN) API to achieve decent device compatibility and operating efficiency. It utilizes Bluetooth Low Energy (BLE) to detect close contact with other people and leverages GPS with fine-grained matching algorithms to verify user information. In addition, to enhance privacy protection, CoAvoid applies fuzzification and obfuscation measures to shelter sensitive data, making both servers and users agnostic to information of both low and high-risk populations. The evaluation demonstrates good efficacy and security of CoAvoid. Compared with four state-of-the-art contact tracing applications, CoAvoid can reduce the size of upload data by at least 90% and reduce the verification time by 92%. More importantly, CoAvoid can preserve user privacy and resist replay and wormhole attacks in all analysis scenarios. IEEE

Stroke network performance during COVID-19 pandemic: A meta-analysis

Background and Aims: The effect of the COVID pandemic on stroke networks performance are unclear, particularly with consideration of drip & ship versus mothership models. We systematically reviewed and metaanalyzed variations in stroke admissions, rate and timing of reperfusion treatments during the COVID pandemic versus the prepandemic timeframe. Methods: The systematic review followed registered protocol (PROSPERO-CRD42020211535), PRISMA and MOOSE guidelines. We searched MEDLINE, EMBASE and Cochrane CENTRAL until 9/10/ 2020, for studies reporting variations in ischemic stroke admissions, treatment rates and timing in COVID vs control-period. Primary outcome was the weekly admission incidence rate ratio (IRR=admissions during COVID-period/admissions during control-period). Secondary outcomes were (i) changes in rate of patients undergoing reperfusion treatment and (ii) time metrics for pre-and in-hospital phase. Results: Twenty-nine studies were included in qualitative synthesis, with 212960 patients observed for 532 cumulative weeks (325 control-period, 207 COVID-period). COVID-period was associated with a significant reduction in stroke admission rates (IRR=0.69, 95%CI, 0.61-0.79) and a higher relative presentation with large vessel occlusion stroke (RR=1.62, 95%CI, 1.24-2.12). Proportions of patients treated with intravenous thrombolysis remained unchanged, while endovascular treatment increased (RR=1.14, 95%CI, 1.02-1.28). Onset-to-door time was longer for drip&ship compared to mothership model (+32 minutes vs-12 minutes, pmeta-regression =.03). Conclusions: Despite a 35% drop in stroke admissions during the pandemic, proportions of patients receiving reperfusion and time-metrics were not inferior to control-period, justifying allocation of resources to keep stroke networks up and running.

Changes in neuro-endovascular procedural volume during the Covid-19 Pandemic: An international multicenter study

Objective: The effect of Coronavirus disease 2019 (COVID-19) pandemic on performance of neuro-endovascular procedures has not been quantified. Background: The effect of Coronavirus disease 2019 (COVID-19) pandemic on performance of neuro-endovascular procedures has not been quantified. Design/Methods: We performed an audit of performance of neuro-endovascular procedures at 18 institutions (7 countries) for two periods;January to April 2019 and 2020, to identify changes in various core procedures. We divided the region where the hospital was located based on the median value of total number of COVID-19 cases per 100,00 population-into high and low prevalent regions Results: Between 2019 and 2020, there was a reduction in number of cerebral angiograms (30.9% reduction), mechanical thrombectomy (8% reduction), carotid artery stent placement for symptomatic (22.7% reduction) and asymptomatic (43.4% reduction) stenoses, intracranial angioplasty and/or stent placement (45% reduction), and endovascular treatment of unruptured intracranial aneurysms (44.6% reduction) and ruptured (22.9% reduction) and unruptured brain arteriovenous malformations (66.4% reduction). There was an increase in treatment of ruptured intracranial aneurysms (10% increase) and other neuro-endovascular procedures (34.9% increase). There was no relationship between procedural volume change and intuitional location in high or low COVID-19 prevalent regions. The procedural volume reduction was mainly observed in March-April 2020. Conclusions: We provided an international multicenter view of changes in neuro-endovascular practices to better understand the gaps in provision of care and identify individual procedures which are susceptible to change.

Traditional Chinese Medicine guidelines for coronavirus disease 2019

OBJECTIVE: To summarize the evidence from Traditional Chinese Medicine (TCM) practice in the treatment of coronavirus disease 2019 (COVID-19) and provide timely clinical practice guidance. METHODS: The guidelines were developed in accordance with the World Health Organization rapid guideline process. The evidence on TCM for COVID-19 from published guidelines, direct and indirect published clinical evidence, first hand clinical data, and expert experience and consensus were collected. The grading of recommendations assessment, development and evaluation (GRADE) method was used to grade the evidence and make the recommendations. RESULTS: Based on the available evidence, the guidelines recommended 17 Chinese medicines for COVID-19: 2 Chinese herbal granules, 7 Chinese patent medicines, and 8 Chinese herbal injections. CONCLUSION: As the literature search was conducted on March, any subsequent versions of these guidelines require an up-to-date literature review. We hope that the evidence summary in these guidelines will be helpful in global efforts to address COVID-19. (C) 2020 JTCM. All rights reserved.