1.Clinical effects of free superficial temporal fascia flap combined with split-thickness thin skin graft in repairing refractory wounds in the anterior tibia
Zhi ZHANG ; Dongliang ZHANG ; Peng JI ; Jing CHENG ; Dahai HU ; Ke TAO
Journal of Chinese Physician 2024;26(3):337-340
Objective:To observe the clinical effect of free superficial temporal fascia flap combined with split thickness skin transplantation in repairing refractory wounds in the anterior tibia.Methods:Data on 19 patients with soft tissue defects in the anterior tibial region who were admitted to the First Affiliated Hospital of Air Force Medical University from September 2019 to October 2023 and met the inclusion criteria were collected and summarized. Among them, 11 were males and 8 were females, aged 19-70 years old. The wound area was 4.3 cm×5.0 cm-6.8 cm×9.5 cm, and all wounds were accompanied by tendon exposure. 5 patients also had local bone exposure, and 10 patients had varying degrees of local infection. All patients were treated with wound debridement and continuous closed negative pressure drainage to control infection. After controlling the wound infection, an equally large temporal superficial fascia tissue flap was designed and cut according to the size of the wound to repair the wound. At the same time, a scalp split thick skin was taken to cover the fascia flap.Results:All 19 patients with superficial temporal fascia flaps survived, while 2 patients had poor skin flap survival due to subcutaneous hematoma. After re-grafting, the wound healed. After follow-up for 6-24 months, all patients were satisfied with the appearance of the anterior tibial region and had good recovery of ankle joint function. The supply valve area was concealed, without obvious scars, hair loss, baldness and other complications.Conclusions:The use of free superficial temporal fascia flap combined with split thick skin transplantation for repairing anterior tibial wounds has the advantages of strong anti infection ability, thin fascia flap, concealed donor site, and reconstruction of supporting ligaments. It is an ideal repair method for repairing difficult to heal wounds in the anterior tibial area.
2.A trinity strategy for the treatment of multiple orthopedic trauma and assessment of its clinical application
Xiao CHEN ; Guangchao WANG ; Hao ZHANG ; Kaiyang LYV ; Qirong ZHOU ; Yunfei NIU ; Yan HU ; Yuanwei ZHANG ; Zuhao LI ; Hao SHEN ; Jin CUI ; Sicheng WANG ; Zhengrong GU ; Zhen GENG ; Dongliang WANG ; Zhehao FAN ; Shihao SHENG ; Chongru HE ; Jun FEI ; Yunfeng CHEN ; Haodong LIN ; Guohui LIU ; Zhiyong HOU ; Jiacan SU
Chinese Journal of Trauma 2024;40(10):888-896
Objective:To explore the clinical value of a trinity strategy for the treatment of multiple orthopedic trauma.Methods:A retrospective case series study was conducted to analyze the clinical data of 1 267 patients with multiple orthopedic trauma admitted to Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine and the First Affiliated Hospital of Navy Medical University from June 2013 to May 2023, including 862 males and 405 females, aged 18-93 years [(55.2±19.8)years]. Associated injuries included hemorrhagic shock in 632 patients, traumatic wet lung in 274, cranial injuries in 135, abdominal and pelvic bleeding in 116, pneumothorax in 89, urinary injury in 13, and vesical rupture in 8. All the patients were treated with the trinity strategy and the treatment process was divided into the phases of first aid, remodeling, and rehabilitation. The first aid phase focused on stabilizing symptoms and saving lives; the remodeling phase centered on restoring the anatomical structure and alignment; the rehabilitation phase aimed for functional recovery through the integration of both Western and traditional Chinese medicine. The all-cause mortality within 30 days after surgery and fracture healing time were calculated; the excellent and good rates of Constant-Murley shoulder score, Mayo elbow score, Gartland-Werley wrist score, Harris hip score, Hospital for Special Surgery (HSS) knee score and the American Orthopedic Foot & Ankle Society (AOFAS) ankle-hindfoot score at the last follow-up and the overall excellent and good rate of all joint function scores were measured. The short form health survey (SF-36) scores were collected preoperatively and at 6 months postoperatively, including 8 aspects such as physical functioning, physical role, bodily pain, general health, vitality, social functioning, emotional role, and mental health. The incidence of postoperative complications was recorded.Results:All the patients were followed up for 6-18 months [(10.2±4.2)months]. The mortality rate during the acute phase (within 30 days after surgery) was 2.37% with 12 deaths due to hemorrhagic shock, 10 due to traumatic brain injury, 6 due to multiple organ dysfunction syndrome (MODS), and 2 due to pulmonary infection. The average fracture healing time averaged 3.8-18 months [(11.5±4.2)months], with 89.49% of the patients having bone union within 12 months after surgery, 8.93% having bone union within 18 months after surgery, and 1.58% undergoing reoperation. For the patients with internal fixation failure and nonunion, the average healing time was extended to (10.2±2.2)months and (13.7±3.3)months respectively. At the last follow-up, the excellent and good rates of Constant-Murley shoulder score, Mayo elbow score, Gartland-Werley wrist score, Harris hip score, HSS knee score, and AOFAS ankle-hindfoot score were 83.93%, 90.24%, 94.12%, 85.57%, 88.46%, and 92.31% respectively, with an overall excellent and good rate of 89.11%. At 6 months after surgery, the SF-36 scores of all the patients in the eight dimensions,including the physical functioning, physical role, bodily pain, general health, vitality, social functioning, emotional role, and mental health were (74.4±8.6)points, (44.7±14.4)points, (77.4±10.9)points, (68.4±18.2)points, (72.5±16.0)points, (76.8±8.7)points, (49.9±17.6)points, and (72.8±17.9)points, significantly improved compared with those before operation [(63.4±12.7)points, (30.9±17.4)points, (56.4±18.0)points, (55.4±24.7)points, (53.5±21.0)points, (55.8±24.3)points, (36.9±24.0)points, (58.8±21.6)points] ( P<0.01). Complications of different degrees occurred in 214 patients (16.89%), including lung infections in 118 patients (9.31%), lower extremity deep vein thrombosis in 50(3.95%), pressure injuries in 26(2.05%), internal fixation failure in 12(0.95%), and nonunion in 8(0.63%). Conclusions:The trinity strategy provides whole-process management, personalized treatment, and overall rehabilitation for multiple orthopedic trauma. It can decrease mortality, shorten fracture healing time, improve joint function and quality of life, and reduce the incidence of complications.
3.The efficacy of pedicled bladder muscle flap in the repair and reconstruction of urinary tract obstruction
Xuxiao YE ; Yinglong SA ; Chongrui JIN ; Xiaoyong HU ; Dongliang YAN ; Wenxiong SONG ; Jijian WANG ; Rong LYU
Chinese Journal of Urology 2023;44(5):354-358
Objective:To explore the efficacy of pedicled bladder muscle flap in the repair of urinary tract obstruction.Methods:The data of 26 patients with urinary tract obstruction admitted to Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine from March 2016 to June 2021 were retrospectively reviewed. There were 14 males and 12 females, with the age ranged from 2 to 75 years old. Refractory bladder neck obstruction after prostatic hyperplasia surgery in 12 cases, with the age of (70.0±3.5) years old.They all experienced at least 2 times of transurethral stenosis incisionor resection. Transpubic cystostomy tube was placed in 9 patients. Posttraumatic pelvic fractures lead to bladder neck atresia and urethral injury in 6 girls, with the age of (10.5±2.1) years old. The bladder neck atresia and urethral obliteration length was 1-2 cm determined by urethrography. Eight cases suffered ureteral strictures after gynecological myomectomy or ureteroscopy holmium laser lithotripsy(4 cases of each type), including two males and six females, with the age of (55.0±3.2) years old. The length of ureteral stricture or defect was 5-6 cm determined by intravenous urography(IVU) or CT urography(CTU). The patients with bladder neck obstruction underwent the following surgery: The "Y" incision of the bladder and stenosis of the prostate urethra was performed and the pedicled bladder muscle flap was inserted into the normal urethral mucosa to complete the Y-V plasty. In the 6 girl patients, pedicled bladder muscle flap(2-4 cm) augmented reconstruction were performed. All above 18 patients, whose urethral catheter was indwelled for 3-4 weeks, urinary flow rate and urethroscopy examination were performed to evaluate the effect of surgery 4 weeks and 3 months after the operation. As the 8 cases with ureteral strictures, the pedicled bladder muscle flap (7-8 cm) ureteroplasty was performed and the ureteral stent was retained for 4 weeks. Ultrasonography and IVU/CTU were performed 4 weeks and 3 months postoperatively. The patency of the ureteral lumen and whether it is accompanied by hydronephrosis, lower back pain, and urinary tract infection were assessed.Results:All patients underwent pedicled bladder muscle flap reconstructive surgery successfully and no serious complications occurred postoperatively. The patients were followed up for (8.2± 2.2) months. As urethral catheters were removed, 10 patients with refractory neck obstruction could return to normal urination with the urinary flow Q max (17.2±2.8)ml/s, while 2 patient had dysuria and were treated with regular urethral dilatation. The catheter was removed 4 weeks after the reconstructive surgery in 6 girls with bladder neck atresia and urethral injury after posttraumatic pelvic fracture. Five could successfully urinate with the urinary flow Q max of (16.7±1.1)ml/s, and one girl had urinary incontinence, waiting for further operation.The ureteral stent was removed after ureteroplasty in 8 patients. CTU and IVU examination showed no ureters with obstruction.No one had low back pain, discomfort, or urinary tract infection. Conclusions:The reconstruction using the pedicled bladder muscle flap was a convenient, minimally invasive and effective technique for the management of adjacent lower ureters, bladder neck, and proximal urethra.
4.Chinese expert consensus on the diagnosis and treatment of osteoporotic periarticular fracture of the shoulder in the elderly (version 2023)
Yan HU ; Dongliang WANG ; Xiao CHEN ; Zhongmin SHI ; Fengjin ZHOU ; Jianzheng ZHANG ; Yanxi CHEN ; Liehu CAO ; Sicheng WANG ; Jianfei WANG ; Hongliang WANG ; Yong FENG ; Zhimin YING ; Chengdong HU ; Qinglin HAN ; Ming LI ; Xiaotao CHEN ; Zhengrong GU ; Biaotong HUANG ; Liming XIONG ; Yunfei ZHANG ; Zhiwei WANG ; Baoqing YU ; Yong WANG ; Lei ZHANG ; Lei YANG ; Peijian TONG ; Ximing LIU ; Qiang ZHOU ; Feng NIU ; Weiguo YANG ; Wencai ZHANG ; Shijie CHEN ; Jinpeng JIA ; Qiang YANG ; Tao SHEN ; Bin YU ; Peng ZHANG ; Yong ZHANG ; Jun MIAO ; Kuo SUN ; Haodong LIN ; Yinxian YU ; Jinwu WANG ; Kun TAO ; Daqian WAN ; Lei WANG ; Xin MA ; Chengqing YI ; Hongjian LIU ; Kun ZHANG ; Guohui LIU ; Dianying ZHANG ; Zhiyong HOU ; Xisheng WENG ; Yingze ZHANG ; Jiacan SU
Chinese Journal of Trauma 2023;39(4):289-298
Periarticular fracture of the shoulder is a common type of fractures in the elderly. Postoperative adverse events such as internal fixation failure, humeral head ischemic necrosis and upper limb dysfunction occur frequently, which seriously endangers the exercise and health of the elderly. Compared with the fracture with normal bone mass, the osteoporotic periarticular fracture of the shoulder is complicated with slow healing and poor rehabilitation, so the clinical management becomes more difficult. At present, there is no targeted guideline or consensus for this type of fracture in China. In such context, experts from Youth Osteoporosis Group of Chinese Orthopedic Association, Orthopedic Expert Committee of Geriatrics Branch of Chinese Association of Gerontology and Geriatrics, Osteoporosis Group of Youth Committee of Chinese Association of Orthopedic Surgeons and Osteoporosis Committee of Shanghai Association of Chinese Integrative Medicine developed the Chinese expert consensus on the diagnosis and treatment of osteoporotic periarticular fracture of the shoulder in the elderly ( version 2023). Nine recommendations were put forward from the aspects of diagnosis, treatment strategies and rehabilitation of osteoporotic periarticular fracture of the shoulder, hoping to promote the standardized, systematic and personalized diagnosis and treatment concept and improve functional outcomes and quality of life in elderly patients with osteoporotic periarticular fracture of the shoulder.
5.Guideline for the diagnosis and treatment of chronic refractory wounds in orthopedic trauma patients (version 2023)
Yuan XIONG ; Bobin MI ; Chenchen YAN ; Hui LI ; Wu ZHOU ; Yun SUN ; Tian XIA ; Faqi CAO ; Zhiyong HOU ; Tengbo YU ; Aixi YU ; Meng ZHAO ; Zhao XIE ; Jinmin ZHAO ; Xinbao WU ; Xieyuan JIANG ; Bin YU ; Dianying ZHANG ; Dankai WU ; Guangyao LIU ; Guodong LIU ; Qikai HUA ; Mengfei LIU ; Yiqiang HU ; Peng CHENG ; Hang XUE ; Li LU ; Xiangyu CHU ; Liangcong HU ; Lang CHEN ; Kangkang ZHA ; Chuanlu LIN ; Chengyan YU ; Ranyang TAO ; Ze LIN ; Xudong XIE ; Yanjiu HAN ; Xiaodong GUO ; Zhewei YE ; Qisheng ZHOU ; Yong LIU ; Junwen WANG ; Ping XIA ; Biao CHE ; Bing HU ; Chengjian HE ; Guanglin WANG ; Dongliang WANG ; Fengfei LIN ; Jiangdong NI ; Aiguo WANG ; Dehao FU ; Shiwu DONG ; Lin CHEN ; Xinzhong XU ; Jiacan SU ; Peifu TANG ; Baoguo JIANG ; Yingze ZHANG ; Xiaobing FU ; Guohui LIU
Chinese Journal of Trauma 2023;39(6):481-493
Chronic refractory wound (CRW) is one of the most challengeable issues in clinic due to complex pathogenesis, long course of disease and poor prognosis. Experts need to conduct systematic summary for the diagnosis and treatment of CRW due to complex pathogenesis and poor prognosis, and standard guidelines for the diagnosis and treatment of CRW should be created. The Guideline forthe diagnosis and treatment of chronic refractory wounds in orthopedic trauma patients ( version 2023) was created by the expert group organized by the Chinese Association of Orthopedic Surgeons, Chinese Orthopedic Association, Chinese Society of Traumatology, and Trauma Orthopedics and Multiple Traumatology Group of Emergency Resuscitation Committee of Chinese Medical Doctor Association after the clinical problems were chosen based on demand-driven principles and principles of evidence-based medicine. The guideline systematically elaborated CRW from aspects of the epidemiology, diagnosis, treatment, postoperative management, complication prevention and comorbidity management, and rehabilitation and health education, and 9 recommendations were finally proposed to provide a reliable clinical reference for the diagnosis and treatment of CRW.
6.Construction and experimental research of atrophic bone nonunion organoid on chip based on vascularization mechanism
Yan HU ; Hao ZHANG ; Han LIU ; Chenyang ZHOU ; Jinlong LIU ; Xiaoqun LI ; Jin CUI ; Qirong ZHOU ; Xiaolin WANG ; Xiao CHEN ; Dongliang WANG ; Jiacan SU
Chinese Journal of Orthopaedics 2023;43(24):1673-1680
Objective:To design and construct a bone nonunion organoid on chip and explore the mechanism of aseptic bone nonunion.Methods:First a semi-open microfluidic chip was designed, on which human bone marrow mesenchymal stromal cells (BMSC), human fetal lung fibroblast 1, (HFL1) and human umbilical vein endothelial cells (HUVEC) were co-cultured, and a three-dimensional organ on chip system was established. Different proportions of HFL1 and HUVEC were co-cultured with BMSC, which were divided into the control group (HFL1∶HUVEC=1∶1), the fibrosis group (HFL1∶HUVEC=3∶1) and the vascularization group (HFL1∶HUVEC=1∶3). The osteogenic differentiation of BMSC was observed by alkaline phosphatase (ALP) and Alizarin red staining. The transcription level of osteogenic marker genes SP7, RUNX2, ALPL, and BGLAP, and vascularization related genes KDR and VWF were analyzed by qPCR. The expression levels of RUNX2 and ALP were determined by Western Blot. Results:In the co-culture system of BMSCs, HFL1, and HUVECs, BMSCs exhibited normal growth and apparent biomineralization behavior. Endothelial cells were capable of forming structured vascular networks, confirming the successful establishment of the system. Compared to the baseline group, the fibrotic group showed no significant decrease in BMSC osteogenic differentiation. The relative expression levels of the mineralization marker genes ALPL and BGLAP were 0.55±0.19 ( P<0.001) and 0.42±0.27 ( P<0.001), respectively. Vascularization genes KDR and VWF were downregulated, with relative expression levels of 0.49±0.17 ( P<0.001) and 0.49±0.21 ( P<0.001). In contrast, in the vascularized group, BMSC osteogenic differentiation genes SP7, RUNX2, ALPL, and BGLAP were upregulated, with relative expression levels of 2.91±0.52 ( P<0.001), 3.83±1.87 ( P<0.001), 3.22±1.29 ( P<0.001), and 5.21±1.46 ( P<0.001), respectively. Vascularization genes KDR and VWF were also upregulated, with relative expressions of 8.24±2.84 ( P<0.001) and 5.32±1.67 ( P<0.001). Western blot results indicated increased expression of RUNX2 and ALP in the vascularized group and decreased expression in the fibrotic group. Conclusion:The bone nonunion organoid on chip could partially simulate the local microenvironment of bone nonunion. Fibrosis may lead to a significant decrease in bone formation ability and vascularization level, which might be an important reason for the occurrence of aseptic bone nonunion.
7.Epidemiological investigation of a case with SARS-CoV-2 infection associated with overseas countries at an international harbor
Dongliang ZHANG ; Bo YI ; Yi CHEN ; Qunxiong HU ; Feng LING ; Xiao MA ; Song LEI ; Hongjun DONG ; Hongxia NI ; Yang MAO ; Qiaofang LI ; Yaorong CHEN ; Ye LU ; Zhenyu GONG ; Jian CAI ; Zhiping CHEN ; Jun LÜ ; Guozhang XU
Journal of Preventive Medicine 2022;34(4):380-384
Objective:
To investigate the origin of infection and risk factors of a case with SARS-CoV-2 infection associated with overseas countries in the Ningbo-Zhoushan Port, Zhejiang Province, so as to provide the evidence for improving the COVID-19 control measures at ports.
Methods:
Ningbo Center for Disease Control and Prevention ( CDC ) and Beilun CDC conducted case finding and epidemiological surveys immediately after being informed. The general information, history of vaccination and the travel during the latest 14 days were collected from the positive case, and all close contacts were tracked. Saliva samples were collected for SARS-CoV-2 nucleic acid testing and whole-genome sequencing, and the sequencing results were aligned with the GISAID's EpiCoV database. The origin of infection and transmission route of the positive case was investigated.
Results:
A case was identified positive for SARS-CoV-2 nucleic acid during company M's routine screening in the Ningbo-Zhoushan Port on August 10, 2021, and was confirmed positive for SARS-CoV-2 nucleic acid by Beilun CDC and Ningbo CDC on August 11. Whole-genome sequencing showed SARS-CoV-2 B.1.617.2 ( Delta ) variant, which shared the highest homology with the virus sequence uploaded by Russia on June, 2021 ( Russia/MOW-RII-MH27356S/2021 ). The case was a bundling worker for overseas container ships, and reported communicated with foreign boatmen and contacted materials without protected interventions on the SINOKOR AKITA Container Ship between August 4 and 5, 2021. This ship anchored at Vladivostok, Russia from July 27 to 29, anchored at Ningbo Harbor on August 4, and departed on August 5. Then, 11 boatmen from this ship were tested positive for SARS-CoV-2 nucleic acid on August 8. One asymptomatic case was reported in this epidemic; 254 close contacts and 617 secondary close contacts were identified, and all were tested negative for SARS-CoV-2 nucleic acid. No new cases with SARS-CoV-2 infections were detected until August 25, 2021, and the emergency response was therefore terminated.
Conclusions
The infection was a sporadic COVID-19 epidemic associated with overseas countries, which was caused by Delta variant infection through contacts with foreign boatmen or materials by a bundling worker in Ningbo-Zhoushan Port; fortunately, no epidemic spread occurred. Intensified closed-loop management and increased frequency of SARS-CoV-2 nucleic acid test among high-risk populations, and improving the precision and rapid emergency treatment of COVID-19 epidemics are required for the containment of COVID-19 at ports.
8.Analysis of chemical ingredients of modified Shenqi Dihuang decoction by UPLC-LTQ-Orbitrap-MS
Zhong WAN ; Wangzhenzu LIU ; Mingyue TAN ; Dongliang XU ; Cheng HU ; Wanli JI
Journal of Pharmaceutical Practice 2022;40(3):231-237
Objective To analyze the chemical compounds of Shenqi Dihuang decoction by the ultraperformance liquid chromatography coupled with linear quadrupole ion trap-orbitrap mass spectrometry (UPLC-LTQ-Orbitrap-MS). Methods Warters ACQUITY UPLC HSS T3 (2.1 mm ×100 mm, 1.8 μm) was used as chromatographic column with mobile phase: 0.1% formic acid water (A)-0.1% formic acid acetonitrile (B) with gradient elution, and flow rate was 0.3 ml/min. Electrospray ion source (ESI) and an electrostatic field orbital ion trap mass analyzer were adopted, which was used to collect mass spectrometry fragment information with positive and negative ion modes, by comparing with the relative retention time of the reference substance. In addition, the fragment information of the mass spectrum was used to identify the compounds. The accurate identification of the chemical components in Shenqi Dihuang decoction was confirmed with literature. Results The study found that UPLC-LTQ-Orbitrap-MS technology could be used to identify 62 chemical components, including 13 aromatic acids, 9 flavonoids, 8 saponins, and 5 aromatic amines, 3 keto acids, 2 phenols, 1 aromatic quinone and other ingredients in Shenqi Dihuang decoction. Conclusion The identification analysis method in this study was efficient and accurate, which could be applied to the identification and analysis of chemical components in Shenqi Dihuang decoction and provided the important experimental data for the research on the material basis and mechanism.
9.Expert consensus on diagnosis, prevention and treatment of perioperative lower extremity vein thrombosis in orthopedic trauma patients (2022 edition)
Wu ZHOU ; Faqi CAO ; Ruiyin ZENG ; Baoguo JIANG ; Peifu TANG ; Xinbao WU ; Bin YU ; Zhiyong HOU ; Jian LI ; Jiacan SU ; Guodong LIU ; Baoqing YU ; Zhi YUAN ; Jiangdong NI ; Yanxi CHEN ; Dehao FU ; Peijian TONG ; Dongliang WANG ; Dianying ZHANG ; Peng ZHANG ; Yunfei ZHANG ; Feng NIU ; Lei YANG ; Qiang YANG ; Zhongmin SHI ; Qiang ZHOU ; Junwen WANG ; Yong WANG ; Chengjian HE ; Biao CHE ; Meng ZHAO ; Ping XIA ; Liming XIONG ; Liehu CAO ; Xiao CHEN ; Hui LI ; Yun SUN ; Liangcong HU ; Yan HU ; Mengfei LIU ; Bobin MI ; Yuan XIONG ; Hang XUE ; Ze LIN ; Yingze ZHANG ; Yu HU ; Guohui LIU
Chinese Journal of Trauma 2022;38(1):23-31
Lower extremity deep vein thrombosis (DVT) is one of the main complications in patients with traumatic fractures, and for severe patients, the DVT can even affect arterial blood supply, resulting in insufficient limb blood supply. If the thrombus breaks off, pulmonary embolism may occur, with a high mortality. The treatment and rehabilitation strategies of thrombosis in patients with lower extremity fractures have its particularity. DVT in traumatic fractures patients has attracted extensive attention and been largely studied, and the measures for prevention and treatment of DVT are constantly developing. In recent years, a series of thrombosis prevention and treatment guidelines have been updated at home and abroad, but there are still many doubts about the prevention and treatment of DVT in patients with different traumatic fractures. Accordingly, on the basis of summarizing the latest evidence-based medical evidence at home and abroad and the clinical experience of the majority of experts, the authors summarize the clinical treatment and prevention protocols for DVT in patients with traumatic fractures, and make this consensus on the examination and assessment, treatment, prevention and preventive measures for DVT in patients with different fractures so as to provide a practicable approach suitable for China ′s national conditions and improve the prognosis and the life quality of patients.
10.Analysis on infectivity of COVID-19 patients before and after last negative nucleic acid test
Yanru CHU ; Yanwu ZHANG ; Song LEI ; Yi CHEN ; Dongliang ZHANG ; Xiaomin GU ; Xuying LAO ; Haibo WANG ; Xiandong SHEN ; Qunxiong HU ; Bo YI ; Enfu CHEN ; Guozhang XU
Chinese Journal of Epidemiology 2022;43(6):841-845
Objective:To investigate the infection rate in close contacts of COVID-19 patients before and after the last negative nucleic acid test, evaluate the effect of dynamic nucleic acid test in determining the infectivity of COVID-19 patients.Methods:Dynamic nucleic acid test results of COVID-19 cases were collected in a retrospective cohort study. COVID-19 cases with negative nucleic acid test results before their first positive nucleic acid tests were selected as study subjects. Close contacts of the index cases and the secondary close contacts were kept isolation for medical observation to assess their risk of infection.Results:This study included 89 confirmed cases from two local COVID-19 epidemics in Ningbo. A total of 5 609 close contacts were surveyed, the overall infection rate was 0.20%. No close contacts of the COVID-19 cases before the last negative nucleic acid test were infected, and the infection rate in the close contacts of the COVID-19 cases after the last negative nucleic acid test was 1.33%, all of these close contacts lived together with the index cases. No secondary close contacts were infected.Conclusion:COVID-19 patient becomes infectious after the last nucleic acid is negative, and has no infectivity before the last nucleic acid negative.


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