Spatial heterogeneity affects predictions from early-curve fitting of pandemic outbreaks: a case study using population data from Denmark.

The modelling of pandemics has become a critical aspect in modern society. Even though artificial intelligence can help the forecast, the implementation of ordinary differential equations which estimate the time development in the number of susceptible, (exposed), infected and recovered (SIR/SEIR) individuals is still important in order to understand the stage of the pandemic. These models are based on simplified assumptions which constitute approximations, but to what extent this are erroneous is not understood since many factors can affect the development. In this paper, we introduce an agent-based model including spatial clustering and heterogeneities in connectivity and infection strength. Based on Danish population data, we estimate how this impacts the early prediction of a pandemic and compare this to the long-term development. Our results show that early phase SEIR model predictions overestimate the peak number of infected and the equilibrium level by at least a factor of two. These results are robust to variations of parameters influencing connection distances and independent of the distribution of infection rates.

Clinical patterns, recovery time and prolonged impact of COVID-19 illness in international athletes: the UK experience.

OBJECTIVES: To report COVID-19 illness pattern, symptom duration and time loss in UK elite athletes. METHODS: Observational, clinical and database review of athletes with symptomatic COVID-19 illness managed within the UK Sports Institutes. Athletes were classified as confirmed (positive SARS-CoV-2 PCR or antibody tests) or probable (consistent clinical features) COVID-19. Clinical presentation was characterised by the predominant symptom focus (eg, upper or lower respiratory illness). Time loss was defined as days unavailable for full sport participation and comparison was made with a 2016-2019 respiratory illness dataset from the same surveillance system. RESULTS: Between 24 February 2020 and 18 January 2021, 147 athletes (25 Paralympic (17%)) with mean (SD) age 24.7 (5.2) years, 37% female, were diagnosed with COVID-19 (76 probable, 71 confirmed). Fatigue was the most prevalent symptom (57%), followed by dry cough (50%) and headache (46%). The median (IQR) symptom duration was 10 (6-17) days but 14% reported symptoms >28 days. Median time loss was 18 (12-30) days, with 27% not fully available >28 days from initial date of infection. This was greater than our historical non-COVID respiratory illness comparator; 6 days, 0-7 days (p<0.001) and 4% unavailable at 28 days. A lower respiratory phenotype (ie, including dyspnoea±chest pain±cough±fever) was present in 18% and associated with a higher relative risk of prolonged symptoms risk ratio 3.0 (95% CI: 1.4 to 6.5) and time loss 2.1 (95% CI: 1.2 to 3.5). CONCLUSIONS: In this cohort, COVID-19 largely resulted in a mild, self-limiting illness. The presence of lower respiratory tract features was associated with prolonged illness and a delayed return to sport.

Assessing the need for transfer to the intensive care unit for Coronavirus-19 disease: Epidemiology and risk factors.

BACKGROUND: Although many patients with coronavirus disease 2019 (Covid-19) require direct admission to the intensive care unit (ICU), some are sent after admission. Clinicians require an understanding of this phenomenon and various risk stratification approaches for recognizing these subjects. METHODS: We examined all Covid-19 patients sent initially to a ward who subsequently required care in the ICU. We examined the timing transfer and attempted to develop a risk score based on baseline variables to predict progressive disease. We evaluated the utility of the CURB-65 score at identifying the need for ICU transfer. RESULTS: The cohort included 245 subjects (mean age 59.0 ± 14.2 years, 61.2% male) and 20% were eventually sent to the ICU. The median time to transfer was 2.5 days. Approximately 1/3rd of patients were not moved until day 4 or later and the main reason for transfer (79.2%) was worsening respiratory failure. A baseline absolute lymphocyte count (ALC) of ≤0.8 103/ml and a serum ferritin ≥1000 ng/ml were independently associated with ICU transfer. Co-morbid illnesses did not correlate with eventual ICU care. Neither a risk score based on a low ALC and/or high ferritin nor the CURB-65 score performed well at predicting need for transfer. CONCLUSION: Covid-19 patients admitted to general wards face a significant risk for deterioration necessitating ICU admission and respiratory failure can occur late in this disease. Neither baseline clinical factors nor the CURB-65 score perform well as screening tests to categorize these subjects as likely to progress to ICU care.