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Background Subways are typical congregate settings and may facilitate aerosol transmission of viruses. However, quantified transmission probability estimates are lacking. Purpose To model spread and diffusion of respiratory aerosols in subways by simulation and calculation of infection probabilities. Methods The internal environment of carriages of Shanghai Metro Line 10 was used to establish a study scene. The movement of tiny particles was simulated using the turbulent model. Trend analysis of infection probabilities and viral quantum doses was conducted in a closed subway carriage scene by a quantum emission-infection probability model. Results Under a typical twelve-vent air conditioning configuration, respiratory droplet aerosols within a subway carriage dispersed rapidly throughout various regions due to airflow, with limited short-term diffusion to other carriages. Concurrently, owing to the uncertainty of airflow patterns, the airflow might circulate and converge within carriages, causing delayed outward dispersion or hindered dispersion of droplet aerosols upon entry into these zones. Passengers boarding the carriage could exacerbate the formation of these zones. When the air conditioning system functioned adequately (air exchange rate=23.21 h−1), the probability of a virus carrier transmitting the virus to other passengers within the same carriage via aerosol transmission was approximately 3.8%. However, in the event of air conditioning system failure (air exchange rate=0.5 h−1), this probability escalated dramatically to 30%. Furthermore, a super-spreader (with virus spreading exceeding 90% of the average) elevated the infection probability to 14.9%. Additionally, due to the complexity of turbulence within the carriage, if local diffusion occurred in 1/2 zones of a carriage, the anticipated infection probability would increase to 8.9%, or during the morning or evening rush hours leading to elevated aerosol concentrations, the infection probability would rise to 4.7%. The subway transmission probability for common coronaviruses diminished to as low as 0.9%. Conclusion Combined computational fluid dynamics and infection probability analysis reveals that in the prevalent twelve-vent air conditioning configurations, despite being a major transportation hub with substantial spatial-temporal overlap, the internal space of subway carriages exhibits a certain level of resistance to virus aerosol transmission owing to built-in ventilation capabilities. However, turbulence and passenger positioning may lead to localized hovering of droplet aerosols, thereby increase the risk of virus transmission. Furthermore, super-spreaders, poor operational status of built-in air conditioning system, and high passenger volume at morning or evening peak hours exert profound effects on virus transmission and infection probability.
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ObjectiveTo study whether COVID-19 infection may be associated with increased hospitalization and mortality from other diseases. DesignCohort study. SettingThe UK Biobank. ParticipantsAll subjects in the UK Biobank with available hospitalization records and alive as of 31-Jan-2020 (N= 412,096; age 50-87). Main outcome measuresWe investigated associations of COVID-19 with hospitalization and mortality due to different diseases post-infection. We conducted a comprehensive survey on disorders from all systems (up to 135 disease categories). Multivariable Cox and Poisson regression was conducted controlling for main confounders. For sensitivity analysis, we also conducted separate analysis for new-onset and recurrent cases, and other analysis such as the prior event rate adjustment(PERR) approach to minimize effects of unmeasured confounders. We also performed association analyses stratified by vaccination status. Time-dependent effects on subsequent hospitalization and mortality were also tested. ResultsCompared to individuals with no known history of COVID-19, those with severe COVID-19 (requiring hospitalization) exhibited higher hazards of hospitalization and/or mortality due to multiple disorders (median follow-up=608 days), including disorders of respiratory, cardiovascular, neurological, gastrointestinal, genitourinary and musculoskeletal systems. Increased hazards of hospitalizations and/or mortality were also observed for injuries due to fractures, various infections and other non-specific symptoms. These results remained largely consistent after sensitivity analyses. Severe COVID-19 was also associated with increased all-cause mortality (HR=14.700, 95% CI: 13.835-15.619). Mild (non-hospitalized) COVID-19 was associated with modestly increased risk of all-cause mortality (HR=1.237, 95% CI 1.037-1.476) and mortality from neurocognitive disorders, as well as hospital admission from a few disorders such as aspiration pneumonitis, musculoskeletal pain and other general signs/symptoms. All-cause mortalities and hospitalizations from other disorders post-infection were generally higher in the pre-vaccination era. The deleterious effect of COVID-19 was observed to wane over time, with maximum HR in the initial phase. ConclusionsIn conclusion, this study revealed increased risk of hospitalization and mortality from a wide variety of pulmonary and extra-pulmonary diseases after COVID-19, especially for severe infections. Mild disease was also associated with increased all-cause mortality. Causality however cannot be established due to observational nature of the study. Further studies are required to replicate our findings.
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BackgroundMore than 170 million cases of COVID-19 have been reported worldwide. It has been proposed that psychiatric disorders may be risk factors and/or consequences of COVID-19 infection. However, observational studies could be affected by confounding bias. MethodsWe performed bi-directional two-sample Mendelian randomization (MR) analysis to evaluate causal relationships between liability to COVID-19 (and severe/critical infection) and a wide range of neuropsychiatric disorders or traits. We employed the latest GWAS summary statistics from the COVID-19 Host Genetics Initiative. A variety of MR methods including those accounting for horizontal pleiotropy were used. ResultsOverall we observed evidence that liability to COVID-19 or severe infection may be causally associated with higher risks of post-traumatic stress disorder (PTSD), bipolar disorder (BD) (especially BD II), schizophrenia (SCZ), attention deficit hyperactivity disorder (ADHD) and suicidal thought (ST) when compared to the general population. On the other hand, liability to a few psychiatric traits/disorders, for example ADHD, alcohol and opioid use disorders may be causally associated with higher risks of COVID-19 infection or severe disease. In genetic correlation analysis, cannabis use disorder, ADHD, and anxiety showed significant and positive genetic correlation with critical or hospitalized infection. All the above findings passed multiple testing correction at a false discovery rate (FDR)<0.05. For pneumonia, in general we observed a different pattern of associations, with bi-directional positive associations with depression- and anxiety-related phenotypes. ConclusionsIn summary, this study provides evidence for tentative bi-directional causal associations between liability to COVID-19 (and severe infection) and a number of neuropsychiatric disorders. Further replications and prospective studies are required to verify the findings.
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10.3969/j.issn.2095-4344.2013.24.024
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Objective To summarize the clinical experience of treatment of recurred urinary stone.Methods The patients who needed to be treated again from 1998 to 2002 were reviewed.Results Patients with recurred urinary stone were differentiated by symptom,the causation of recurred stone and operation.Conclusion The pointed step must be adopted based on the clinical character of recurred urinary stone.Preventing against recurred and choosing appropriate method can improve the treatment effect.
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Objective To study the curative effect of transurethral incision for male urethral stricture or atresia. Methods A retrospective) review was made on 55 male patients with urethral stricture or atresia treated by transurethral incision. Results The success rate of the operation on one session was 90.9% (50/55), while the remaining 5 patients were cured by two times of operations.Forty-seven patients were followed for 6~12 months (mean,10 months).Urethral dilatation was performed for once within 1 week after the remorval of catheter in 10 patients,for 3~5 times within 3 months after operation in 21 patients,and after the third postoperative month in 16 patients. Conclusions Transurethral incision for male urethral stricture or atresia is effective.
