Mathematical modelling of COVID-19 transmission and mitigation strategies in the population of Ontario, Canada.
- 作者列表："Tuite AR","Fisman DN","Greer AL
BACKGROUND:Physical-distancing interventions are being used in Canada to slow the spread of severe acute respiratory syndrome coronavirus 2, but it is not clear how effective they will be. We evaluated how different nonpharmaceutical interventions could be used to control the coronavirus disease 2019 (COVID-19) pandemic and reduce the burden on the health care system. METHODS:We used an age-structured compartmental model of COVID-19 transmission in the population of Ontario, Canada. We compared a base case with limited testing, isolation and quarantine to scenarios with the following: enhanced case finding, restrictive physical-distancing measures, or a combination of enhanced case finding and less restrictive physical distancing. Interventions were either implemented for fixed durations or dynamically cycled on and off, based on projected occupancy of intensive care unit (ICU) beds. We present medians and credible intervals from 100 replicates per scenario using a 2-year time horizon. RESULTS:We estimated that 56% (95% credible interval 42%-63%) of the Ontario population would be infected over the course of the epidemic in the base case. At the epidemic peak, we projected 107 000 (95% credible interval 60 760-149 000) cases in hospital (non-ICU) and 55 500 (95% credible interval 32 700-75 200) cases in ICU. For fixed-duration scenarios, all interventions were projected to delay and reduce the height of the epidemic peak relative to the base case, with restrictive physical distancing estimated to have the greatest effect. Longer duration interventions were more effective. Dynamic interventions were projected to reduce the proportion of the population infected at the end of the 2-year period and could reduce the median number of cases in ICU below current estimates of Ontario's ICU capacity. INTERPRETATION:Without substantial physical distancing or a combination of moderate physical distancing with enhanced case finding, we project that ICU resources would be overwhelmed. Dynamic physical distancing could maintain health-system capacity and also allow periodic psychological and economic respite for populations.
背景: 加拿大正在使用物理距离干预措施来减缓新型冠状病毒的传播，但尚不清楚其效果如何。我们评估了不同的非药物干预措施如何用于控制冠状病毒疾病 2019 (新型冠状病毒肺炎) 大流行和减轻卫生保健系统的负担。 方法: 我们在加拿大安大略省的人群中使用了新型冠状病毒肺炎传播的年龄结构分区模型。我们将具有有限测试、隔离和检疫base病例与以下情况进行了比较: 增强病例发现、限制性物理距离措施，或者加强病例发现和较少限制的物理距离的组合。根据重症监护病房 (ICU) 床位的预计占用情况，实施固定持续时间或动态循环的干预措施。我们使用 2 年的时间范围呈现每个场景 100 次重复的中位数和可信间隔。 结果: 我们估计，56% (95% 可信区间 42%-63%) 的安大略省人口base基础病例的流行过程中会被感染。在流行高峰，我们预测医院 (非ICU) 107 000 (95% 可信区间 60 760-149 000) 病例和 55 500 (95% 可信区间 32 700-75 200) ICU中的病例。对于固定持续时间的情景，预计所有干预措施都会延迟和降低相对于base病例的流行高峰的高度，限制性物理距离估计效果最大。较长时间的干预更有效。预计动态干预措施将在 2 年期间结束时减少感染人口的比例，并可能将ICU的中位病例数降低到安大略省ICU能力的当前估计值以下。 解释: 如果没有实质性的物理距离或中度物理距离与增强的病例发现相结合，我们预测ICU资源将不堪重负。动态身体距离可以保持健康系统的能力，也允许人口周期性的心理和经济喘息。
METHODS::Since mid-December of 2019, coronavirus disease 2019 (COVID-19) infection has been spreading from Wuhan, China. The confirmed COVID-19 patients in South Korea are those who came from or visited China. As secondary transmissions have occurred and the speed of transmission is accelerating, there are rising concerns about community infections. The 54-year old male is the third patient diagnosed with COVID-19 infection in Korea. He is a worker for a clothing business and had mild respiratory symptoms and intermittent fever in the beginning of hospitalization, and pneumonia symptoms on chest computerized tomography scan on day 6 of admission. This patient caused one case of secondary transmission and three cases of tertiary transmission. Hereby, we report the clinical findings of the index patient who was the first to cause tertiary transmission outside China. Interestingly, after lopinavir/ritonavir (Kaletra, AbbVie) was administered, β-coronavirus viral loads significantly decreased and no or little coronavirus titers were observed.
METHODS::In December 2019, a novel coronavirus (2019-nCoV) caused an outbreak in Wuhan, China, and soon spread to other parts of the world. It was believed that 2019-nCoV was transmitted through respiratory tract and then induced pneumonia, thus molecular diagnosis based on oral swabs was used for confirmation of this disease. Likewise, patient will be released upon two times of negative detection from oral swabs. However, many coronaviruses can also be transmitted through oral-fecal route by infecting intestines. Whether 2019-nCoV infected patients also carry virus in other organs like intestine need to be tested. We conducted investigation on patients in a local hospital who were infected with this virus. We found the presence of 2019-nCoV in anal swabs and blood as well, and more anal swab positives than oral swab positives in a later stage of infection, suggesting shedding and thereby transmitted through oral-fecal route. We also showed serology test can improve detection positive rate thus should be used in future epidemiology. Our report provides a cautionary warning that 2019-nCoV may be shed through multiple routes.
METHODS::There is a current worldwide outbreak of a new type of coronavirus (2019-nCoV), which originated from Wuhan in China and has now spread to 17 other countries. Governments are under increased pressure to stop the outbreak spiraling into a global health emergency. At this stage, preparedness, transparency, and sharing of information are crucial to risk assessments and beginning outbreak control activities. This information should include reports from outbreak sites and from laboratories supporting the investigation. This paper aggregates and consolidates the virology, epidemiology, clinical management strategies from both English and Chinese literature, official news channels, and other official government documents. In addition, by fitting the number of infections with a single-term exponential model, we report that the infection is spreading at an exponential rate, with a doubling period of 1.8 days.