ABSTRACT
This paper proposed a quarantine-susceptible-exposed-infectious-resistant (QSEIR) model which considers the unprecedented strict quarantine measures in almost the whole of China to resist the epidemic. We estimated model parameters from published information with the statistical method and stochastic simulation, we found the parameters that achieved the best simulation test result. The next stage involved quantitative predictions of future epidemic developments based on different containment strategies with the QSEIR model, focused on the sensitivity of the outcomes to different parameter choices in mainland China. The main results are as follows. If the strict quarantine measures are being retained, the peak value of confirmed cases would be in the range of [52438, 64090] and the peak date would be expected in the range February 7 to February 19, 2020. During March18-30, 2020, the epidemic would be controlled. The end date would be in the period from August 20 to September 1, 2020. With 80% probability, our prediction on the peak date was 4 days ahead of the real date, the prediction error of the peak value is 0.43%, both estimates are much closer to the observed values compared with published studies. The sensitive analysis indicated that the quarantine measures (or with vaccination) are the most effective containment strategy to control the epidemic, followed by measures to increase the cured rate (like finding special medicine). The long-term simulation result and sensitive analysis in mainland China showed that the QSEIR model is stable and can be empirically validated. It is suggested that the QSEIR model can be applied to predict the development trend of the epidemic in other regions or countries in the world. In mainland China, the quarantine measures cant be relaxed before the end of March 2020. China can fully resume production with appropriate anti-epidemic measures beginning in early April 2020. The results of this study also implied that other countries now facing the epidemic outbreaks should act more decisively and take in time quarantine measures though it may have negative short-term public and economic consequences.
ABSTRACT
Objective To analyze the factors which may affect postoperative patency of microsurgical vasoepididymostomy (VE).Methods Ninety-four patients underwent VEs from September 2014 to June 2016 in the Department of Urology,Peking University Third Hospital,with average age of (30.7 ± 4.8) years,and body mass index (BMI) of (25.1 ± 3.0) kg/m2.Semen analyses were performed 1 month,3 months and 5 to 6 months after the operation.The following semen analyses were performed every 3-6 months thereafter.Patency was defined by finding sperms in twice or more analyses during the followup until August 2017.Patients were followed up by face-to-face or telephone interview.Seven factors (age,BMI,bilateral or unilateral anastomosis,anastomosis sites,the adjustment of anastomosis sites,motility and quantity of sperms found in epididymal fluid) were analyzed by Chi-square analysis and multifactor logistic regression analysis.Results Eighty-two patients were followed up (87.2％,82/94) while 12 patients were lost of follow-up.The mean follow-up time was 19 months.Sperms were found in the ejaculate in 59 patients postoperatively.The overall patency rate was 72.0％ (59/82),and natural paternity rate was 32.8％ (19/58).Patients ≤28 years old and those ＞28 years old had patency rates of 89.3％ (25/28) and 63.0％ (34/54,P =0.012),respectively.Patients with BMI ＜26.0 kg/m2 and BMI≥26.0 kg/m2 had patency rates of 80.4％ (41/51) and 58.1％ (18/31,P =0.029),respectively.Patency rate of bilateral surgery was 72.1％ (44/61) and of unilateral surgery was 71.4％ (44/62,P =0.727).Patency rate of caput anastomosis achieved 75.0％ (15/20) and of corpus/caudal anastomosis was 71.0％ (44/62,P =0.727).Patency rates of patients with and without adjustment of anastomosis sites were 77.8％ (7/9) and 71.2％ (52/73,P =0.680),respectively.Patency rates of a lot,a few,motile and seldom-motile sperms in epididymal fluid were 74.3％ (55/74) vs.50.0％ (4/8,P =0.146) and 70.0％ (28/40) vs.73.8％ (31/42,P =0.701),respectively.Multifactor logistic regression analysis showed that age was well associated with patency rate (OR=4.705,95％CI 1.181-18.742,P=0.028).Conclusions Age ≤28 years is an independent factor leading to higher patency rates.Patients with lower BMIs and younger could have higher patency rates.Factors of anastomosis sides,anastomosis sites,the adjustment of anastomosis sites,motility and quantity of sperms found in epididymal fluid showed no statistical difference in patency rates.
