Comparison of COVID-19 outcomes among shielded and non-shielded populations.

Many western countries used shielding (extended self-isolation) of people presumed to be at high-risk from COVID-19 to protect them and reduce healthcare demand. To investigate the effectiveness of this strategy, we linked family practitioner, prescribing, laboratory, hospital and death records and compared COVID-19 outcomes among shielded and non-shielded individuals in the West of Scotland. Of the 1.3 million population, 27,747 (2.03%) were advised to shield, and 353,085 (26.85%) were classified a priori as moderate risk. COVID-19 testing was more common in the shielded (7.01%) and moderate risk (2.03%) groups, than low risk (0.73%). Referent to low-risk, the shielded group had higher confirmed infections (RR 8.45, 95% 7.44-9.59), case-fatality (RR 5.62, 95% CI 4.47-7.07) and population mortality (RR 57.56, 95% 44.06-75.19). The moderate-risk had intermediate confirmed infections (RR 4.11, 95% CI 3.82-4.42) and population mortality (RR 25.41, 95% CI 20.36-31.71) but, due to their higher prevalence, made the largest contribution to deaths (PAF 75.30%). Age ≥ 70 years accounted for 49.55% of deaths. In conclusion, in spite of the shielding strategy, high risk individuals were at increased risk of death. Furthermore, to be effective as a population strategy, shielding criteria would have needed to be widely expanded to include other criteria, such as the elderly.

Assessing the feasibility and effectiveness of household-pooled universal testing to control COVID-19 epidemics.

Outbreaks of SARS-CoV-2 are threatening the health care systems of several countries around the world. The initial control of SARS-CoV-2 epidemics relied on non-pharmaceutical interventions, such as social distancing, teleworking, mouth masks and contact tracing. However, as pre-symptomatic transmission remains an important driver of the epidemic, contact tracing efforts struggle to fully control SARS-CoV-2 epidemics. Therefore, in this work, we investigate to what extent the use of universal testing, i.e., an approach in which we screen the entire population, can be utilized to mitigate this epidemic. To this end, we rely on PCR test pooling of individuals that belong to the same households, to allow for a universal testing procedure that is feasible with the limited testing capacity. We evaluate two isolation strategies: on the one hand pool isolation, where we isolate all individuals that belong to a positive PCR test pool, and on the other hand individual isolation, where we determine which of the individuals that belong to the positive PCR pool are positive, through an additional testing step. We evaluate this universal testing approach in the STRIDE individual-based epidemiological model in the context of the Belgian COVID-19 epidemic. As the organisation of universal testing will be challenging, we discuss the different aspects related to sample extraction and PCR testing, to demonstrate the feasibility of universal testing when a decentralized testing approach is used. We show through simulation, that weekly universal testing is able to control the epidemic, even when many of the contact reductions are relieved. Finally, our model shows that the use of universal testing in combination with stringent contact reductions could be considered as a strategy to eradicate the virus.

Increased Screen Use on Days With Increased Perceived COVID-19-Related Confinements-A Day Level Ecological Momentary Assessment Study.

Introduction: Coronavirus 2019 (COVID-19) quickly evolved into a global pandemic in early 2020, and most countries enforced social confinements to reduce transmission. This seems to dovetail with increasing, potentially problematic, screen use habits, such as gaming and "binge-watching." Yet, the subjective experience of the common confinements may vary not only between individuals depending on age, sex, and living conditions (i.e., living alone) but also within individuals from day to day: confinements might interfere with habitual activity schedules more strongly on some days than on others. Such dynamic confinement experience has not been studied in relation to screen use yet but might guide targeted intervention. Method: In total, 102 participants (n = 83 female, n = 80 university students) completed 14 days of ecological momentary assessment during a COVID-19-related lockdown in Germany and Austria. Each evening, they indicated the extent to which they felt restricted by confinements in their social and work lives and whether they engaged in unusually high and intense levels of television watching, social media use, news consumption, internet surfing, and gaming. They also reported on how much they experienced their day to be structured. Results: Experienced work confinements were positively associated with social media usage. Further, work confinements were positively associated with gaming in males and with news consumption, especially in individuals living alone. Social confinements were positively associated with watching television especially in younger participants and with social media consumption in younger participants. Higher experienced day structure was related to less television watching, gaming, and internet surfing but more news consumption. Discussion: Screen use behaviors increased with higher confinements within person, dependent on sex, age, and living situation. Such knowledge allows tailoring on the person level (who should be addressed?) and the time level (when should interventions be scheduled?) as the negative consequences of excessive screen use behaviors on mental and physical health are well-documented. One potential low-threshold intervention might be day-structuring.

Mining Google and Apple mobility data: temporal anatomy for COVID-19 social distancing.

We employ the Google and Apple mobility data to identify, quantify and classify different degrees of social distancing and characterise their imprint on the first wave of the COVID-19 pandemic in Europe and in the United States. We identify the period of enacted social distancing via Google and Apple data, independently from the political decisions. Our analysis allows us to classify different shades of social distancing measures for the first wave of the pandemic. We observe a strong decrease in the infection rate occurring two to five weeks after the onset of mobility reduction. A universal time scale emerges, after which social distancing shows its impact. We further provide an actual measure of the impact of social distancing for each region, showing that the effect amounts to a reduction by 20-40% in the infection rate in Europe and 30-70% in the US.

Extensions of the SEIR model for the analysis of tailored social distancing and tracing approaches to cope with COVID-19.

In the context of the COVID-19 pandemic, governments worldwide face the challenge of designing tailored measures of epidemic control to provide reliable health protection while allowing societal and economic activity. In this paper, we propose an extension of the epidemiological SEIR model to enable a detailed analysis of commonly discussed tailored measures of epidemic control-among them group-specific protection and the use of tracing apps. We introduce groups into the SEIR model that may differ both in their underlying parameters as well as in their behavioral response to public health interventions. Moreover, we allow for different infectiousness parameters within and across groups, different asymptomatic, hospitalization, and lethality rates, as well as different take-up rates of tracing apps. We then examine predictions from these models for a variety of scenarios. Our results visualize the sharp trade-offs between different goals of epidemic control, namely a low death toll, avoiding overload of the health system, and a short duration of the epidemic. We show that a combination of tailored mechanisms, e.g., the protection of vulnerable groups together with a "trace & isolate" approach, can be effective in preventing a high death toll. Protection of vulnerable groups without further measures requires unrealistically strict isolation. A key insight is that high compliance is critical for the effectiveness of a "trace & isolate" approach. Our model allows to analyze the interplay of group-specific social distancing and tracing also beyond our case study in scenarios with a large number of groups reflecting, e.g., sectoral, regional, or age differentiation and group-specific behavioural responses.

Impact of coronavirus disease 2019 (COVID-19) lockdown on in-hospital mortality and surgical activity in elective digestive resections: A nationwide cohort analysis.

BACKGROUND: The outbreak of coronavirus disease 2019 (COVID-19) infection has led to the reorganization of hospital care in several countries. The objective was to report the postoperative mortality after elective digestive resections in a nationwide cohort during the lockdown period. METHODS: This analytic study was performed using a national billing database (the Programme de Médicalisation des Systèmes d'Informations). Patients who underwent elective digestive resections were divided in 2 groups: the lockdown group defined by hospital admissions between March 17 and May 11, 2020; and the control group, defined by hospital admissions during the corresponding period in 2019. Groups were matched on propensity score, geographical region, and surgical procedure. The primary outcome was the postoperative mortality. RESULTS: The overall population included 15,217 patients: 9,325 patients in the control group and 5,892 in the lockdown group. The overall surgical activity was decreased by 37% during the lockdown period. The overall in-hospital mortality during the hospital stay was 2.7%. After matching and adjustment, no difference in mortality between groups was reported (OR = 1.05; 95% CI: 0.83-1.34; P = .669). An asymptomatic COVID-19 infection was a risk factor for a 2-fold increased mortality, whereas a symptomatic COVID-19 infection was associated with a 10-fold increased mortality. CONCLUSION: Despite a considerable reduction in the surgical activity for elective digestive resections during the lockdown period, mortality remained stable on a nationwide scale in COVID-free patients. These findings support that systematic COVID-19 screening should be advocated before elective gastrointestinal surgery and that all efforts should be made to maintain elective surgical resection for cancer during the second wave in COVID-free patients.

On the Threshold of Release of Confinement in an Epidemic SEIR Model Taking into Account the Protective Effect of Mask.

We present a classic SEIR model taking into account the daily movements of individuals in different places. The model also takes into account partial confinement of individuals. This model is coupled with a model of protection against the epidemic by the use of masks. We are studying the effects of combined confinement and protection measures on the dynamics of the epidemic. We consider a constant proportion of asymptomatic people. We assume that symptomatic infected people may change their urban travel behavior due to the disease which causes them to travel less to places where they used to move and to stay at home more often. We present a sensitivity study with respect to the parameters. We show that the combination of the use of masks with almost complete release of confinement makes it possible to avoid the occurrence of a secondary peak of the epidemic. The model predicts that a total release of confinement can be successful for an epidemic of [Formula: see text] if on average a proportion of [Formula: see text] of the population wears masks of [Formula: see text] efficacy. However, if [Formula: see text] of the population remains confined, the same goal can be achieved with a proportion of [Formula: see text] of the population wearing masks with efficacy of the order of [Formula: see text].

Impact of the COVID-19 shutdown on orthopedic trauma numbers and patterns in an academic Level I Trauma Center in Berlin, Germany.

BACKGROUND: The COVID-19 pandemic led to the implementation of drastic shutdown measures worldwide. While quarantine, self-isolation and shutdown laws helped to effectively contain and control the spread of SARS-CoV-2, the impact of COVID-19 shutdowns on trauma care in emergency departments (EDs) remains elusive. METHODS: All ED patient records from the 35-day COVID-19 shutdown (SHUTDOWN) period were retrospectively compared to a calendar-matched control period in 2019 (CTRL) as well as to a pre (PRE)- and post (POST)-shutdown period in an academic Level I Trauma Center in Berlin, Germany. Total patient and orthopedic trauma cases and contacts as well as trauma causes and injury patterns were evaluated during respective periods regarding absolute numbers, incidence rate ratios (IRRs) and risk ratios (RRs). FINDINGS: Daily total patient cases (SHUTDOWN vs. CTRL, 106.94 vs. 167.54) and orthopedic trauma cases (SHUTDOWN vs. CTRL, 30.91 vs. 52.06) decreased during the SHUTDOWN compared to the CTRL period with IRRs of 0.64 and 0.59. While absolute numbers decreased for most trauma causes during the SHUTDOWN period, we observed increased incidence proportions of household injuries and bicycle accidents with RRs of 1.31 and 1.68 respectively. An RR of 2.41 was observed for injuries due to domestic violence. We further recorded increased incidence proportions of acute and regular substance abuse during the SHUTDOWN period with RRs of 1.63 and 3.22, respectively. CONCLUSIONS: While we observed a relevant decrease in total patient cases, relative proportions of specific trauma causes and injury patterns increased during the COVID-19 shutdown in Berlin, Germany. As government programs offered prompt financial aid during the pandemic to individuals and businesses, additional social support may be considered for vulnerable domestic environments.

Association of the COVID-19 lockdown with smoking, drinking and attempts to quit in England: an analysis of 2019-20 data.

AIM: To examine changes in smoking, drinking and quitting/reduction behaviour following the COVID-19 lockdown in England. DESIGN/SETTING: Monthly cross-sectional surveys representative of the adult population in England, aggregated before (April 2019-February 2020) versus after (April 2020) lockdown. PARTICIPANTS: A total of 20 558 adults (≥ 16 years). MEASUREMENTS: The independent variable was the timing of the COVID-19 lockdown (before versus after March 2020). Dependent variables were: prevalence of smoking and high-risk drinking, past-year cessation and quit attempts (among past-year smokers), past-year attempts to reduce alcohol consumption (among high-risk drinkers) and use of evidence-based (e.g. prescription medication/face-to-face behavioural support) and remote support [telephone support/websites/applications (apps)] for smoking cessation and alcohol reduction (among smokers/high-risk drinkers who made a quit/reduction attempt). Covariates included age, sex, social grade, region and level of nicotine and alcohol dependence (as relevant). FINDINGS: The COVID-19 lockdown was not associated with a significant change in smoking prevalence [17.0% (after) versus 15.9% (before), odds ratio (OR) = 1.09, 95% CI = 0.95-1.24], but was associated with increases in quit attempts [39.6 versus 29.1%, adjusted odds ratio (ORadj ) = 1.56, 95% CI = 1.23-1.98], quit success (21.3 versus 13.9%, ORadj  = 2.01, 95% CI = 1.22-3.33) and cessation (8.8 versus 4.1%, ORadj  = 2.63, 95% CI = 1.69-4.09) among past-year smokers. Among smokers who tried to quit, there was no significant change in use of evidence-based support (50.0 versus 51.5%, ORadj  = 1.10, 95% CI = 0.72-1.68) but use of remote support increased (10.9 versus 2.7%, ORadj  = 3.59, 95% CI = 1.56-8.23). Lockdown was associated with increases in high-risk drinking (38.3 versus 25.1%, OR = 1.85, CI = 1.67-2.06), but also alcohol reduction attempts by high-risk drinkers (28.5 versus 15.3%, ORadj  = 2.16, 95% CI = 1.77-2.64). Among high-risk drinkers who made a reduction attempt, use of evidence-based support decreased (1.2 versus 4.0%, ORadj  = 0.23, 95% CI = 0.05-0.97) and there was no significant change in use of remote support (6.9 versus 6.1%, ORadj  = 1.32, 95% CI = 0.64-2.75). CONCLUSIONS: Following the March 2020 COVID-19 lockdown, smokers and high-risk drinkers in England were more likely than before lockdown to report trying to quit smoking or reduce alcohol consumption and rates of smoking cessation and use of remote cessation support were higher. However, high-risk drinking prevalence increased post-lockdown and use of evidence-based support for alcohol reduction by high-risk drinkers decreased with no compensatory increase in use of remote support.

Spatio-temporal distribution characteristics and influencing factors of COVID-19 in China.

In December 2019, corona virus disease 2019 (COVID-19) has broken out in China. Understanding the distribution of disease at the national level contributes to the formulation of public health policies. There are several studies that investigating the influencing factors on distribution of COVID-19 in China. However, more influencing factors need to be considered to improve our understanding about the current epidemic. Moreover, in the absence of effective medicine or vaccine, the Chinese government introduced a series of non-pharmaceutical interventions (NPIs). However, assessing and predicting the effectiveness of these interventions requires further study. In this paper, we used statistical techniques, correlation analysis and GIS mapping expression method to analyze the spatial and temporal distribution characteristics and the influencing factors of the COVID-19 in mainland China. The results showed that the spread of outbreaks in China's non-Hubei provinces can be divided into five stages. Stage I is the initial phase of the COVID-19 outbreak; in stage II the new peak of the epidemic was observed; in stage III the outbreak was contained and new cases decreased; there was a rebound in stage IV, and stage V led to level off. Moreover, the cumulative confirmed cases were mainly concentrated in the southeastern part of China, and the epidemic in the cities with large population flows from Wuhan was more serious. In addition, statistically significant correlations were found between the prevalence of the epidemic and the temperature, rainfall and relative humidity. To evaluate the NPIs, we simulated the prevalence of the COVID-19 based on an improved SIR model and under different prevention intensity. It was found that our simulation results were compatible with the observed values and the parameter of the time function in the improved SIR model for China is a = - 0.0058. The findings and methods of this study can be effective for predicting and managing the epidemics and can be used as an aid for decision makers to control the current and future epidemics.

Estimating the effect of selective border relaxation on COVID-19 in New Zealand.

AIMS: We developed a model, updated daily, to estimate undetected COVID-19 infections exiting quarantine following selectively opening New Zealand's borders to travellers from low-risk countries. METHODS: The prevalence of infectious COVID-19 cases by country was multiplied by expected monthly passenger volumes to predict the rate of arrivals. The rate of undetected infections entering the border following screening and quarantine was estimated. Level 1, Level 2 and Level 3 countries were defined as those with an active COVID-19 prevalence of up to 1/105, 10/105 and 100/105, respectively. RESULTS: With 65,272 travellers per month, the number of undetected COVID-19 infections exiting quarantine is 1 every 45, 15 and 31 months for Level 1, Level 2 and Level 3 countries, respectively. The overall rate of undetected active COVID-19 infections exiting quarantine is expected to increase from the current 0.40 to 0.50 per month, or an increase of one extra infection every 10 months. CONCLUSIONS: Loosening border restrictions results in a small increase in the rate of undetected COVID-19 infections exiting quarantine, which increases from the current baseline by one infection every 10 months. This information may be useful in guiding decision-making on selectively opening of borders in the COVID-19 era.

The impact of national lockdown on nutritional status of children with inflammatory bowel disease.

BACKGROUND: The COVID-19 pandemic has had wide-reaching primary and secondary health implications. The UK government implemented a national lockdown to slow the rate of infection at the end of March 2020, lasting until early summer 2020. The results from a UK nationwide survey suggest the majority of inflammatory bowel disease patients were followed up using technology-enabled care services (TECS) during this time. We therefore aimed to explore the impact of the pandemic on nutritional status of children with inflammatory bowel disease, focusing on the effect of national lockdown from March to early summer 2020. METHODS: A retrospective study was conducted. All patients with a diagnosis of inflammatory bowel disease, aged <18 years, and under the care of Southampton Children's Hospital were eligible for inclusion. Those patients who attended an outpatient appointment during time period 1 (November 2019 to February 2020), and following the period of national lockdown, time period 2 (July to November 2020), were included in the analysis. RESULTS: In total, 116 patients had paired measures. Using the World Health Organization criteria of nutritional status, 19% (n = 22/116) were mildly malnourished with a body mass index Z score (BMIZ) < -1. In this group, the mean BMIZ was -1.3 ± 0.9 at time point 1 versus -1.9 ± 0.9 at time point 2 (p = 0.03). The mean BMIZ score of those children who were overweight at time point 1 was 1.2 ± 1.2 versus 1.6 ± 1.4 at time point 2 (p = 0.2) During the period of lockdown, 27% of malnourished children (n = 6/22), 2% of normally nourished children (BMIZ > -1 to < 1) (n = 1/51) (p ≤ 0.0001) and none of the overweight children (BMIZ > 1) (n = 0/43) children (p ≤ 0.0001) had a TECS nutrition review. CONCLUSIONS: Dietetic reviews were severely restricted during the first national lockdown. Patients with low BMIZ prior to lockdown became more malnourished. During the ongoing pandemic, it is important to identify those children with nutrition risk, focusing support on this group of children.

Increased frequency of severe diabetic ketoacidosis at type 1 diabetes onset among children during COVID-19 pandemic lockdown: an observational cohort study.

INTRODUCTION: On March 11, 2020 the WHO announced a coronavirus disease 2019 (COVID-19) pandemic. Lockdown restrictions, compromised access to medical care and fear of potential exposure to SARS-CoV-2 have forced patients with non-COVID-19 illnesses such as type 1 diabetes (T1D) to stay home. This situation can lead to delay in T1D diagnosis and insulin treatment resulting in rapid progression to diabetic ketoacidosis (DKA) and therefore increased risk of complications and death.  . AIM: The aim of this study was to evaluate the frequency and severity of DKA at the onset of T1D in children diagnosed in our department during COVID-19 pandemic lockdown from March 2020 till May 2020 in comparison to corresponding period of the previous year. . MATERIAL AND METHODS: We collected data of children with newly diagnosed T1D. DKA was defined according to ISPAD guidelines. . RESULTS: The study cohort comprised 34 children in group 2020 and 52 in group 2019 with an average age 9.90 ±4.9 vs. 9.59±4.7 years with mean HbA1c 12.9 ±2.4 vs. 11.5 ±2.2%, respectively. The incidence of DKA was higher by 12% in group 2020 vs. 2019 (52.94% vs 40.38%; p = 0.276).  Regarding the DKA severity (2020 vs. 2019) 32.35% vs. 11.54% were severe (p = 0.026), 17.65 vs. 13% were moderate (p = 0.759), and 2.94 vs. 15.38% were mild (p = 0.081). None of the analyzed patients were COVID-19 positive. CONCLUSIONS: During the COVID-19 pandemic lockdown changes in society and health care system, the DKA rate has increased by 12 percentage points with more severe cases noted in children with newly diagnosed T1D. Regular education of the whole society about the symptoms of diabetes could contribute to faster diagnosis of T1D and reduction of DKA prevalence. .

COVID-19 outbreak in Brazil: adherence to national preventive measures and impact on people's lives, an online survey.

BACKGROUND: The first case of COVID-19 infection was diagnosed in Brazil 26th February 2020. By March 16th, physical distancing and confinement measures were implemented by the Brazilian government. Little is known about how these measures were followed up by the Brazilian people and their impact on daily routine. METHODS: In early April 2020, using an online platform, we organized an online survey among adults living in Brazil about their COVID-19 preventive behavior and impact on their daily routine. RESULTS: Data from 23,896 respondents were analyzed (mean age: 47.4 years). Due to COVID-19 restrictions, half (51.1%) of the professionals reported working from home. Regular handwashing was practiced by 98.7% of participants; 92.6% reported adhering to the 1.5-2 m physical distancing rule, but only 45.5% wore a face mask when going outside. While 29.3% of respondents found it relatively easy to stay at home, indoor confinement was extremely difficult for 7.9% of participants. Moreover, 11% of participants were extremely worried about their health during the COVID-19 epidemic. Younger people, male, persons living in a rural area/village or popular neighbourhoods, students and workers reported less preventive behaviour. CONCLUSION: Restrictive measures markedly affected the daily and professional routines of Brazilians. Participants showed a satisfactory level of adherence to national COVID-19 prevention guidelines. Qualitative and follow-up studies are needed to monitor the impact of COVID-19 in the Brazilian society.

Purchasing, consumption, demographic and socioeconomic variables associated with shifts in alcohol consumption during the COVID-19 pandemic.

INTRODUCTION AND AIMS: Restrictions introduced to reduce the spread of COVID-19 have had major impacts on the living circumstances of Australians. This paper aims to provide insight into shifts in alcohol consumption and associated factors during the epidemic. DESIGN AND METHODS: A cross-sectional convenience sample of 2307 Australians aged 18 and over who drank at least monthly was recruited through social media. Respondents were asked about their alcohol consumption and purchasing in 2019 prior to the epidemic plus similar questions about their experiences in the month prior to being surveyed between 29 April and 16 May 2020. RESULTS: Reports of average consumption before (3.53 drinks per day [3.36, 3.71 95% confidence interval]) and during (3.52 [3.34, 3.69]) the pandemic were stable. However, young men and those who drank more outside the home in 2019 reported decreased consumption during the pandemic, and people with high levels of stress and those who bulk-bought alcohol when restrictions were announced reported an increase in consumption relative to those who did not. DISCUSSION AND CONCLUSIONS: A reported increase in consumption among those experiencing more stress suggests that some people may have been drinking to cope during the epidemic. Conversely, the reported decrease in consumption among those who drank more outside of their home in 2019 suggests that closing all on-trade sales did not result in complete substitution of on-premise drinking with home drinking in this group. Monitoring of relevant subgroups to assess long-term changes in consumption in the aftermath of the epidemic is recommended.

Estimating the Effect of Social Distancing Interventions on COVID-19 in the United States.

Since its global emergence in 2020, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused multiple epidemics in the United States. When medical treatments for the virus were still emerging and a vaccine was not yet available, state and local governments sought to limit its spread by enacting various social-distancing interventions, such as school closures and lockdowns; however, the effectiveness of these interventions was unknown. We applied an established, semimechanistic Bayesian hierarchical model of these interventions to the spread of SARS-CoV-2 from Europe to the United States, using case fatalities from February 29, 2020, up to April 25, 2020, when some states began reversing their interventions. We estimated the effects of interventions across all states, contrasted the estimated reproduction numbers before and after lockdown for each state, and contrasted the predicted number of future fatalities with the actual number of fatalities as a check of the model's validity. Overall, school closures and lockdowns were the only interventions modeled that had a reliable impact on the time-varying reproduction number, and lockdown appears to have played a key role in reducing that number to below 1.0. We conclude that reversal of lockdown without implementation of additional, equally effective interventions will enable continued, sustained transmission of SARS-CoV-2 in the United States.

Mechanistic transmission modeling of COVID-19 on the Diamond Princess cruise ship demonstrates the importance of aerosol transmission.

Several lines of existing evidence support the possibility of airborne transmission of coronavirus disease 2019 (COVID-19). However, quantitative information on the relative importance of transmission pathways of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains limited. To evaluate the relative importance of multiple transmission routes for SARS-CoV-2, we developed a modeling framework and leveraged detailed information available from the Diamond Princess cruise ship outbreak that occurred in early 2020. We modeled 21,600 scenarios to generate a matrix of solutions across a full range of assumptions for eight unknown or uncertain epidemic and mechanistic transmission factors. A total of 132 model iterations met acceptability criteria (R2 > 0.95 for modeled vs. reported cumulative daily cases and R2 > 0 for daily cases). Analyzing only these successful model iterations quantifies the likely contributions of each defined mode of transmission. Mean estimates of the contributions of short-range, long-range, and fomite transmission modes to infected cases across the entire simulation period were 35%, 35%, and 30%, respectively. Mean estimates of the contributions of larger respiratory droplets and smaller respiratory aerosols were 41% and 59%, respectively. Our results demonstrate that aerosol inhalation was likely the dominant contributor to COVID-19 transmission among the passengers, even considering a conservative assumption of high ventilation rates and no air recirculation conditions for the cruise ship. Moreover, close-range and long-range transmission likely contributed similarly to disease progression aboard the ship, with fomite transmission playing a smaller role. The passenger quarantine also affected the importance of each mode, demonstrating the impacts of the interventions.

Sustainable COVID-19 Mitigation: Wuhan Lockdowns, Health Inequities, and Patient Evacuation.

The world is urgently looking for ways to flatten the coronavirus disease 2019 (COVID-19) curve, and many governments have resorted to implementing strict lockdowns, as researchers show the effectiveness of China's approaches in containing the virus. However, this paper argues that the draconian lockdowns instituted in Wuhan, Hubei, China, may have actually contributed to intensifying patient surges and incapacitating local health systems. Medical aids were rushed to Hubei and new hospitals were rapidly built, however, the healthcare system was still unable to match the staggering increase of patients in the early stages of the lockdowns. The paper proposes using patient evacuation to enhance sustainable COVID-19 mitigation during lockdowns. It demonstrates that patients in Hubei could have been transported to other Chinese provinces where hospitals were under-utilized. This could have theoretically saved thousands of lives by reducing inequities between Hubei and the rest of China in healthcare capacity for treating COVID-19 patients.