1.Construction and validation of prediction models for delayed encephalopathy after acute carbon monoxide poisoning based on machine learning
Yanwu YU ; Yan ZHANG ; Ding YUAN ; Huihui HAO ; Fang YANG ; Hongyi YAN ; Pin JIANG ; Mengnan GUO ; Zhigao XU ; Changhua SUN ; Gaiqin YAN ; Lu CHE ; Jianjun GUO ; Jihong CHEN ; Yan LI ; Yanxia GAO
Chinese Journal of Emergency Medicine 2025;34(10):1403-1409
Objective:s To investigate the risk factors for delayed encephalopathy after acute carbon monoxide poisoning (DEACMP) in patients with acute carbon monoxide poisoning (ACOP) and to develop predictive models based on machine learning algorithms.Methods:Patients with ACOP hospitalized at the First Affiliated Hospital of Zhengzhou University from August 2019 to October 2024 were included, with the occurrence of DEACMP as the outcome measure. The dataset was randomly divided into training and validation sets at a ratio of 7:3. Lasso regression was used to select features influencing the outcome in training sets. Nine machine learning models—including Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Support Vector Machine (SVM)—were constructed. Receiver operating characteristic (ROC) curves were plotted and the area under the curve (AUC) calculated for each model. Calibration curves were used to assess accuracy, and decision curve analysis (DCA) was applied to evaluate clinical utility. The SHapley Additive exPlanations (SHAP) method was employed to visualize and interpret the best-performing model.Results:A total of 264 ACOP patients were included, of whom 54 (20.5%) developed DEACMP. Lasso regression identified eight key feature variables. Based on these factors, predictive models were constructed, showing good AUC stability across the nine machine learning models in both training (0.92–0.99) and validation sets (0.85–0.91). The RF model performed best, with an AUC of 0.99 in the training set and 0.90 in the validation set; its calibration curve and DCA curve also demonstrated excellent performance. SHAP analysis of the RF model revealed the importance ranking of factors from highest to lowest as follows: Glasgow Coma Scale (GCS) score, duration of coma, age, history of coronary heart disease, CK-MB level, monocyte count, diastolic blood pressure (DBP), and drinking history.Conclusions:The RF model exhibited the highest predictive performance for DEACMP occurrence in ACOP patients. The influencing factors, ranked in order of importance from highest to lowest, are as follows: GCS score, duration of coma, age, history of coronary heart disease, CK-MB level, monocyte count, DBP, and drinking history.
2.Dynamic assessment of pathological changes at different stages in a mouse model of colitis-associated colon cancer
Lili HUANG ; Fan XIAO ; Guirong CHEN ; Guifang DENG ; Jinbin SONG ; Qun DU ; Yanwu LI
Acta Laboratorium Animalis Scientia Sinica 2025;33(6):802-810
Objective To investigate the dynamic characteristics of intestinal pathological development at different time points in a mouse model of colitis-associated colon cancer.Methods A colitis-cancer model was established in C57BL/6 mice using azoxymethane(AOM)combined with dextran sulfate sodium(DSS).Samples were collected at 7,10,and 14 weeks post-modeling and the spleen index,colon length,mass,and colon mass per unit length were measured.Histopathological changes in the colon were observed by hematoxylin and eosin and Masson staining.Expression levels of the cancer stem cell marker CD44 and Wnt signaling pathway genes Wnt2b,Lrp5,Axin2,and Znrf3 at different pathological stages were detected by reverse transcription quantitative real time PCR.Cancer-associated fibroblasts(FAP),CD44,the proliferation marker Ki67,and goblet cell MUC2 protein were detected by multiple immunofluorescence histochemistry(mIHC)and immunofluorescence.In addition,colon organoids were isolated from model mice at ten and fourteen weeks and cultured in vitro to observe changes in organoid morphology and marker expression.Results AOM/DSS-induced mice showed reduced,distorted,and branched colon crypt structures with a few collagen fibers at 7 weeks,and varying degrees of colon intraepithelial neoplasia,with an increased proportion of high-grade intraepithelial neoplasia over time and increased collagen fiber staining at ten and fourteen weeks.mRNA levels of CD44 and Wnt2b in the colon were significantly increased(P<0.05)and Axin2 was decreased(P<0.01)in model mice compared with control mice at fourteen week,and levels of Wnt2b,Lrp5,and Znrf3 were increased compared with seven-week mice(P<0.01,P<0.05,P<0.01),and Axin2 was decreased(P<0.01).mIHC staining showed increased expression of FAP and CD44 in the colon in model mice at ten and fourteen weeks,with decreased MUC2 expression.Colon organoids showed cystic dilation,especially at fourteen weeks,with more prominent expression of Ki67 and CD44.Conclusions The AOM/DSS-induced mouse model exhibited chronic colonic inflammation,low-grade intraepithelial neoplasia,and high-grade intraepithelial neoplasia at seven,ten,and fourteen weeks,respectively.The pathological microenvironment was characterized by fibroblast activation and abnormal proliferation of epithelial cells.
3.Prognostic analysis of local excision in 153 cases of locally advanced low rectal cancer following neoadjuvant therapy
Hongfeng PAN ; Jiahong YE ; Heyuan ZHU ; Xiaojie WANG ; Yanwu SUN ; Zhifen CHEN ; Zongbin XU ; Shenghui HUANG ; Weizhong JIANG ; Pan CHI ; Ying HUANG
Chinese Journal of Gastrointestinal Surgery 2025;28(11):1250-1259
Objective:To evaluate the short-term and long-term outcomes of patients with locally advanced low rectal cancer who achieved clinical complete response (cCR) or near-clinical complete response (near-cCR) after neoadjuvant chemoradiotherapy (nCRT) and then underwent local excision.Methods:This was a descriptive case series study. Clinical data of patients with low rectal cancer who received neoadjuvant therapy, achieved cCR or near-cCR, underwent local excision, and had complete postoperative follow-up data were retrospectively analyzed. The study period was from May, 2015 to October, 2024, and the patients were treated at Fujian Medical University Union Hospital. Indications for local excision in this study were as follows: pathologically confirmed rectal adenocarcinoma, with the lower edge of the tumor ≤ 6 cm from the anal verge; maximum diameter of the lesion ≤ 2 cm after nCRT; no regional lymph node metastasis detected by transrectal endoscopic ultrasound (ERUS), pelvic magnetic resonance imaging (MRI), or positron emission tomography-computed tomography (PET-CT) after nCRT; MRI showing fibrosis of the primary lesion with a small amount of high signal on diffusion-weighted imaging (DWI), consistent with ymrT0-1 stage; serum carcinoembryonic antigen level within the normal range (< 5 μg/L) after nCRT; complicated with severe underlying diseases such as cardiovascular and cerebrovascular diseases and assessed as unable to tolerate radical surgery through comprehensive evaluation; and signed informed consent for local excision. The contraindications were: colonoscopic pathology indicating poorly differentiated adenocarcinoma or signet ring cell carcinoma; suspected lateral lymph node metastasis before neoadjuvant therapy; patients with residual lesions exceeding 3 cm in range after treatment. A total of 153 patients were included in this study, including 84 males and 69 females. The median age was 62 years, and the median distance from the tumor to the anal verge after neoadjuvant therapy was 4.0 cm. The short-term efficacy indicators of this study included postoperative complications of local excision and postoperative pathological results, and the long-term efficacy indicators included oncological prognosis (3-year cumulative local recurrence rate, 3-year cumulative distant metastasis rate, 3-year progression-free survival, and 3-year overall survival) and anal function at 1 year after surgery evaluated using the Low Anterior Resection Syndrome (LARS) scale where the total score is 42 points such that 0-20 points indicate no LARS, 21-29 points indicate mild LARS, and 30-42 points indicate severe LARS.Results:Postoperative pathology showed 122 cases (79.7%) of ypT0 stage, 10 cases (6.5%) of ypT1 stage, 18 cases (11.8%) of ypT2 stage, and 3 cases (2.0%) of ypT3 stage. The incidence of surgery-related complications was 42.5% (65/153), and the main complications included perianal pain (39.9%, 61/153), intestinal wall incision dehiscence (21.6%, 33/153), and intestinal wall incision infection (18.3%, 28/153). The proportion of patients who received hypofractionated radiotherapy before surgery and developed intestinal wall incision dehiscence was 65.2% (15/23), which was higher than that in the conventional long-course (13.6%, 16/118) and short-course radiotherapy groups (16.7%,2/12) (χ 2=30.55, P<0.001); of the 20 patients who received additional immunotherapy before surgery, 13 developed intestinal wall incision dehiscence was 65.0%, which was higher than that in the group without additional immunotherapy [15.0%(20/133),χ 2=25.66, P<0.001]. The median follow-up time of the entire group was 35.4 months. During the follow-up period, there were 9 cases of postoperative local recurrence, with a 3-year cumulative local recurrence rate of 7.9% and 5 cases of distant metastasis, with a 3-year cumulative distant metastasis rate of 5.0%. The 3-year progression-free survival rate was 89.0%, and the 3-year overall survival rate was 95.9%. At 1 year after surgery, 10 cases (10.5%, 10/95) had severe anal dysfunction, and the median LARS score of the entire group was 5.0 (range: 0-41.0) points. Conclusions:For patients with locally advanced low rectal cancer who achieve cCR or near-cCR after neoadjuvant therapy, local excision results in favorable oncological prognosis and anal function preservation effects; however, the incidence of complications is relatively high.
4.Prognostic analysis of local excision in 153 cases of locally advanced low rectal cancer following neoadjuvant therapy
Hongfeng PAN ; Jiahong YE ; Heyuan ZHU ; Xiaojie WANG ; Yanwu SUN ; Zhifen CHEN ; Zongbin XU ; Shenghui HUANG ; Weizhong JIANG ; Pan CHI ; Ying HUANG
Chinese Journal of Gastrointestinal Surgery 2025;28(11):1250-1259
Objective:To evaluate the short-term and long-term outcomes of patients with locally advanced low rectal cancer who achieved clinical complete response (cCR) or near-clinical complete response (near-cCR) after neoadjuvant chemoradiotherapy (nCRT) and then underwent local excision.Methods:This was a descriptive case series study. Clinical data of patients with low rectal cancer who received neoadjuvant therapy, achieved cCR or near-cCR, underwent local excision, and had complete postoperative follow-up data were retrospectively analyzed. The study period was from May, 2015 to October, 2024, and the patients were treated at Fujian Medical University Union Hospital. Indications for local excision in this study were as follows: pathologically confirmed rectal adenocarcinoma, with the lower edge of the tumor ≤ 6 cm from the anal verge; maximum diameter of the lesion ≤ 2 cm after nCRT; no regional lymph node metastasis detected by transrectal endoscopic ultrasound (ERUS), pelvic magnetic resonance imaging (MRI), or positron emission tomography-computed tomography (PET-CT) after nCRT; MRI showing fibrosis of the primary lesion with a small amount of high signal on diffusion-weighted imaging (DWI), consistent with ymrT0-1 stage; serum carcinoembryonic antigen level within the normal range (< 5 μg/L) after nCRT; complicated with severe underlying diseases such as cardiovascular and cerebrovascular diseases and assessed as unable to tolerate radical surgery through comprehensive evaluation; and signed informed consent for local excision. The contraindications were: colonoscopic pathology indicating poorly differentiated adenocarcinoma or signet ring cell carcinoma; suspected lateral lymph node metastasis before neoadjuvant therapy; patients with residual lesions exceeding 3 cm in range after treatment. A total of 153 patients were included in this study, including 84 males and 69 females. The median age was 62 years, and the median distance from the tumor to the anal verge after neoadjuvant therapy was 4.0 cm. The short-term efficacy indicators of this study included postoperative complications of local excision and postoperative pathological results, and the long-term efficacy indicators included oncological prognosis (3-year cumulative local recurrence rate, 3-year cumulative distant metastasis rate, 3-year progression-free survival, and 3-year overall survival) and anal function at 1 year after surgery evaluated using the Low Anterior Resection Syndrome (LARS) scale where the total score is 42 points such that 0-20 points indicate no LARS, 21-29 points indicate mild LARS, and 30-42 points indicate severe LARS.Results:Postoperative pathology showed 122 cases (79.7%) of ypT0 stage, 10 cases (6.5%) of ypT1 stage, 18 cases (11.8%) of ypT2 stage, and 3 cases (2.0%) of ypT3 stage. The incidence of surgery-related complications was 42.5% (65/153), and the main complications included perianal pain (39.9%, 61/153), intestinal wall incision dehiscence (21.6%, 33/153), and intestinal wall incision infection (18.3%, 28/153). The proportion of patients who received hypofractionated radiotherapy before surgery and developed intestinal wall incision dehiscence was 65.2% (15/23), which was higher than that in the conventional long-course (13.6%, 16/118) and short-course radiotherapy groups (16.7%,2/12) (χ 2=30.55, P<0.001); of the 20 patients who received additional immunotherapy before surgery, 13 developed intestinal wall incision dehiscence was 65.0%, which was higher than that in the group without additional immunotherapy [15.0%(20/133),χ 2=25.66, P<0.001]. The median follow-up time of the entire group was 35.4 months. During the follow-up period, there were 9 cases of postoperative local recurrence, with a 3-year cumulative local recurrence rate of 7.9% and 5 cases of distant metastasis, with a 3-year cumulative distant metastasis rate of 5.0%. The 3-year progression-free survival rate was 89.0%, and the 3-year overall survival rate was 95.9%. At 1 year after surgery, 10 cases (10.5%, 10/95) had severe anal dysfunction, and the median LARS score of the entire group was 5.0 (range: 0-41.0) points. Conclusions:For patients with locally advanced low rectal cancer who achieve cCR or near-cCR after neoadjuvant therapy, local excision results in favorable oncological prognosis and anal function preservation effects; however, the incidence of complications is relatively high.
5.Dynamic assessment of pathological changes at different stages in a mouse model of colitis-associated colon cancer
Lili HUANG ; Fan XIAO ; Guirong CHEN ; Guifang DENG ; Jinbin SONG ; Qun DU ; Yanwu LI
Acta Laboratorium Animalis Scientia Sinica 2025;33(6):802-810
Objective To investigate the dynamic characteristics of intestinal pathological development at different time points in a mouse model of colitis-associated colon cancer.Methods A colitis-cancer model was established in C57BL/6 mice using azoxymethane(AOM)combined with dextran sulfate sodium(DSS).Samples were collected at 7,10,and 14 weeks post-modeling and the spleen index,colon length,mass,and colon mass per unit length were measured.Histopathological changes in the colon were observed by hematoxylin and eosin and Masson staining.Expression levels of the cancer stem cell marker CD44 and Wnt signaling pathway genes Wnt2b,Lrp5,Axin2,and Znrf3 at different pathological stages were detected by reverse transcription quantitative real time PCR.Cancer-associated fibroblasts(FAP),CD44,the proliferation marker Ki67,and goblet cell MUC2 protein were detected by multiple immunofluorescence histochemistry(mIHC)and immunofluorescence.In addition,colon organoids were isolated from model mice at ten and fourteen weeks and cultured in vitro to observe changes in organoid morphology and marker expression.Results AOM/DSS-induced mice showed reduced,distorted,and branched colon crypt structures with a few collagen fibers at 7 weeks,and varying degrees of colon intraepithelial neoplasia,with an increased proportion of high-grade intraepithelial neoplasia over time and increased collagen fiber staining at ten and fourteen weeks.mRNA levels of CD44 and Wnt2b in the colon were significantly increased(P<0.05)and Axin2 was decreased(P<0.01)in model mice compared with control mice at fourteen week,and levels of Wnt2b,Lrp5,and Znrf3 were increased compared with seven-week mice(P<0.01,P<0.05,P<0.01),and Axin2 was decreased(P<0.01).mIHC staining showed increased expression of FAP and CD44 in the colon in model mice at ten and fourteen weeks,with decreased MUC2 expression.Colon organoids showed cystic dilation,especially at fourteen weeks,with more prominent expression of Ki67 and CD44.Conclusions The AOM/DSS-induced mouse model exhibited chronic colonic inflammation,low-grade intraepithelial neoplasia,and high-grade intraepithelial neoplasia at seven,ten,and fourteen weeks,respectively.The pathological microenvironment was characterized by fibroblast activation and abnormal proliferation of epithelial cells.
6.Epidemiological characteristics of hand, foot, and mouth disease in Haishu District from 2011 to 2022
XIAO Wenqiang ; BAO Kaifang ; LI Baojun ; ZHANG Yanwu ; TONG Siwei ; CHEN Yi
Journal of Preventive Medicine 2024;36(11):976-979
Objective:
To investigate the epidemiological characteristics of hand, foot, and mouth disease (HFMD) in Haishu District, Ningbo City, Zhejiang Province from 2011 to 2022, so as to provide the basis for the formulation of HFMD prevention and control strategies.
Methods:
Data of HFMD in Haishu District from 2011 to 2022 were collected from Chinese Disease Prevention and Control Information System, and the epidemiological and etiological characteristics were analyzed using a descriptive epidemiological method. The trends in incidence of HFMD and prevalence of positive etiological tests were analyzed using annual percent change (APC).
Results:
A total of 33 334 cases of HFMD were reported in Haishu District from 2011 to 2022, with an average annual reported incidence of 279.16/105, showing no significant trend (APC=-5.492%, P>0.05). The average annual reported incidence of HFMD was lower after the enterovirus 71 vaccine was launched (from 2017 to 2022) than before (from 2011 to 2016; 219.69/105 vs. 343.70/105, P<0.05). The incidence of HFMD showed seasonal characteristics, with a peak from May to July. There were 19 720 male and 13 614 female cases, with a male-to-female ratio of 1.45∶1. The age of the HFMD cases ranged from 27 days to 63 years old, and the children aged 5 years and below were predominant (30 657 cases, 91.97%). A total of 1 976 specimens of HFMD cases were collected from 2011 to 2022, and 1 509 enterovirus positive specimens were detected, with a positive rate of 76.37%. The positive rates of enterovirus 71 decreased (APC=-32.599%, P<0.05), the positive rates of coxsackievirus A16 increased (APC=9.226%, P<0.05), while the positive rates of other enteroviruses showed no significant change (APC=0.808%, P>0.05).
Conclusions
The average annual reported incidence of HFMD in Haishu District from 2011 to 2022 decreased after the enterovirus 71 vaccine was launched, with a peak in spring and summer. Children aged 5 years and below were the high-incidence population, and coxsackievirus A16 was the main serotype.
7.Portable head and neck magnetic resonance imaging device in neurosurgery
Hongwei ZHU ; Houminji CHEN ; Long ZENG ; Qingshan XIAO ; Tao XIE ; Yanwu GUO ; Wangming ZHANG ; Qinghua WANG ; Chuanzhi DUAN ; Shizhong ZHANG ; Yiquan KE ; Hongbo GUO
Chinese Journal of Neuromedicine 2023;22(1):58-63
Objective:To explore the clinical application of portable head and neck magnetic resonance imaging (MRI) device in neurosurgery.Methods:A total of 213 patients with brain diseases who were scanned by portable head and neck MRI device in Center of Neurosurgery, Zhujiang Hospital, Southern Medical University from June to September 2022 were selected. The portable head and neck MRI images and 3.0T conventional MRI images of 10 randomly selected patients were compared; the differences in signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of different sequences were analyzed. Thirty-one patients accepted tracheal intubation/tracheotomy, or ventilator-assisted breathing were selected as special patient group, and another 30 patients were as general patient group; the differences in comprehensive diagnostic scores of portable head and neck MRI images were compared. Noise intensity differences in different sequences between 3.0T conventional MRI and portable head and neck MRI were statistically compared. Twenty hospitalized volunteers with normal hearing in our center from July to August 2022 were selected, conventional 3.0T MRI and portable head and neck MRI were performed successively, and the noise intensity of different sequences in them was evaluated by using a 5-point system.Results:Compared with those in 3.0T conventional MRI images, the SNR and CNR of T1WI, T2WI, and Liquid attenuated reverse recovery sequence (FLAIR) sequences in portable head and neck MRI images were significantly lower ( P<0.05). No significant difference was noted in the comprehensive diagnostic scores of portable head and neck MRI images between special patients and general patients ( P>0.05). Compared with that in the 3.0T conventional MRI, the noise intensity of different sequences in portable head and neck MRI was significantly reduced ( P<0.05). These volunteers had significantly reduced noise intensity scores of different sequences in portable head and neck MRI compared with that in conventional 3.0T MRI ( P<0.05). Conclusion:Portable head and neck MRI device is easy to use, enjoying high safety, imaging quality and suitability, which meets the clinical needs for neurosurgery patients.
8.Epidemiological characteristics of reinfection of 2019-nCoV and influencing factors in Ningbo
Yanru CHU ; Yi CHEN ; Song LEI ; Yanwu ZHANG ; Bo YI ; Jianming MA ; Kedong YAN ; Yun WANG ; Baojun LI ; Mengqian LYU ; Guozhang XU ; Dongliang ZHANG
Chinese Journal of Epidemiology 2023;44(9):1402-1407
Objective:To analyze the epidemiological characteristics of reinfection of 2019-nCoV and influencing factors, and provide evidence for effective prevention and control of COVID-19 epidemic.Methods:The incidence data of COVID-19 in Ningbo from January 1, 2020 to November 30, 2022 were collected from the infectious disease surveillance system of Chinese information system for disease control and prevention. The incidence of reinfection of 2019-nCoV was investigated by using questionnaire. logistic regression analysis was used to analyze the influences of gender, age, time interval from the first infection, history of underlying disease, 2019-nCoV vaccination dose and disease severity on the reinfection.Results:A total of 897 previous 2019-nCoV infection cases were investigated, of which 115 experienced the reinfection of 2019-nCoV, the reinfection rate was 12.82%. The interval between the two infections M( Q1, Q3) was 1 052 (504, 1 056) days. Univariate analysis showed that age, 2019-nCoV vaccination dose, history of underlying disease, type of 2019-nCoV variant causing the first infection, time interval from the first infection and severity of the first infection were associated with the reinfection rate (all P<0.05). Multivariate logistic regression analysis showed that the risk for reinfection in age group 30- years was higher than that in age group ≥60 years ( OR=2.10, 95% CI: 1.11-3.97). No reinfection occurred in those with time interval from the first infection of <6 months, and the risk for reinfection was higher in those with the time interval of ≥12 months than in those with the time interval of 6- months ( OR=6.68, 95% CI: 3.46-12.90). The risk for reinfection was higher in the common or mild cases than in the asymptomatic cases ( OR=2.64, 95% CI: 1.18-5.88; OR=2.79, 95% CI: 1.27-6.11). Conclusion:The time interval from the first infection was an important influencing factor for the reinfection of 2019-nCoV, and the probability of the reinfection within 6 months was low.
9.Etiological diagnostic value of cerebrospinal fluid metagenomic next-generation sequencing in central nervous system infection
Cuicui MENG ; Ding YUAN ; Yanwu YU ; Jinzhu WANG ; Jianjun GUO ; Guiying ZHU ; Yimeng WEI ; Jihong CHEN ; Leilei ZHANG ; Yanxia GAO
Chinese Journal of Emergency Medicine 2022;31(4):471-476
Objective:To investigate the etiological diagnostic value of metagenomic sequencing in central nervous system (CNS) infectious diseases.Methods:A total of 170 patients with central nervous system infection admitted to the First Affiliated Hospital of Zhengzhou University from January 2018 to June 2020 were selected as the study subjects according to inclusion and exclusion criteria. General clinical data and pathogen test results were collected. All included patients underwent routine examination and mNGS test, and were divided into the conventional method test group and mNGS test group according to the test results. The measurement data conforming to normal distribution were represented by ± s; The measurement data that did not conform to normal distribution were represented by median and interquartile range. The classification data were expressed by the number of cases and percentage( n,%), and were compared by χ2 test or Fisher's exact test. Consistency test was represented by Kappa value. The detection of pathogenic microorganisms by the two methods and the rule of pathogen spectrum were compared and analyzed. Results:The overall positive rate of mNGS in CNS infectious diseases was higher than that of conventional methods (58.23% vs. 18.82%), and the difference was statistically significant ( P<0.01). Among the 20 samples which were both positive by the two methods, 10 cases were completely pathogenic, 5 cases were partially consistent and 5 cases were completely inconsistent. In the detection of tuberculous nervous system infection, the positive rates were 66.7%, 53.8%, 44.0%, 40.0%, 4.0% in blood T-SPOT, cerebrospinal fluid mNGS, ADA, Mycobacterium tuberculosis DNA and tuberculous specific antibody, respectively. The positive rate of acid-fast staining was 0. The positive rate of mNGS combined with conventional method was 80.8%. Conclusions:The detection rate of mNGS in CNS infection is better than that of conventional methods. However, it does not show obvious superiority in the detection rate of Mycobacterium tuberculosis associated nervous system infection. In general, mNGS detection of pathogenic bacteria is more extensive, which is conducive to a thorough and comprehensive understanding of the bacterial characteristics of central nervous system infection. The combination of the two methods can make up for the deficiency of clinical routine detection to a certain extent, and can maximize the detection rate.
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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