Codelivery of anti-CD47 antibody and chlorin e6 using a dual pH-sensitive nanodrug for photodynamic immunotherapy of osteosarcoma

Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppressive microenvironment severely limits the efficacy of osteosarcoma treatment.The dual pH-sensitive nanocarrier has emerged as an effective antitumor drug delivery system that can selectively release drugs into the acidic tumor microenvironment.Here,we prepared a dual pH-sensitive nanocarrier,loaded with the photosensitizer Chlorin e6(Ce6)and CD47 monoclonal antibodies(aCD47),to deliver synergistic photodynamic and immunotherapy of osteosarcoma.On laser irradiation,Ce6 can generate reactive oxygen species(ROS)to kill cancer cells directly and induces immunogenic tumor cell death(ICD),which further facilitates the dendritic cell maturation induced by blockade of CD47 by aCD47.Moreover,both calreticulin released during ICD and CD47 blockade can accelerate phagocytosis of tumor cells by macrophages,promote antigen presentation,and eventually induce T lymphocyte-mediated antitumor immunity.Overall,the dual pH-sensitive nanodrug loaded with Ce6 and aCD47 showed excellent immune-activating and anti-tumor effects in osteosarcoma,which may lay the theoretical foundation for a novel combination model of osteosarcoma treatment.

Unraveling the mechanism of malancao in treating ulcerative colitis:A multi-omics approach

BACKGROUND Malancao(MLC)is a traditional Chinese medicine with a long history of utilization in treating ulcerative colitis(UC).Nevertheless,the precise molecular mechanisms underlying its efficacy remain elusive.This study leveraged ultrahigh-performance liquid chromatography coupled with exactive mass spectrometry(UHPLC-QE-MS),network pharmacology,molecular docking(MD),and gene microarray analysis to discern the bioactive constituents and the potential mechanism of action of MLC in UC management.AIM To determine the ingredients related to MLC for treatment of UC using multiple databases to obtain potential targets for fishing.METHODS This research employs UHPLC-QE-MS for the identification of bioactive compounds present in MLC plant samples.Furthermore,the study integrates the identified MLC compound-related targets with publicly available databases to elucidate common drug disease targets.Additionally,the R programming language is utilized to predict the central targets and molecular pathways that MLC may impact in the treatment of UC.Finally,MD are conducted using AutoDock Vina software to assess the affinity of bioactive components to the main targets and confirm their therapeutic potential.RESULTS Firstly,through a comprehensive analysis of UHPLC-QE-MS data and public database resources,we identified 146 drug-disease cross targets related to 11 bioactive components.The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis highlighted that common disease drug targets are primarily involved in oxidative stress management,lipid metabolism,atherosclerosis,and other processes.They also affect AGE-RAGE and apoptosis signaling pathways.Secondly,by analyzing the differences in diseases,we identified key research targets.These core targets are related to 11 active substances,including active ingredients such as quercetin and luteolin.Finally,MD analysis revealed the stability of compound-protein binding,particularly between JUNLuteolin,JUN-Quercetin,HSP90AA1-Wogonin,and HSP90AA1-Rhein.Therefore,this suggests that MLC may help alleviate intestinal inflammation in UC,restore abnormal lipid accumulation,and regulate the expression levels of core proteins in the intestine.CONCLUSION The utilization of MLC has demonstrated notable therapeutic efficacy in the management of UC by means of the compound target interaction pathway.The amalgamation of botanical resources,metabolomics,natural products,MD,and gene chip technology presents a propitious methodology for investigating therapeutic targets of herbal medicines and discerning novel bioactive constituents.

Covert Communication with a Spectrum Sharing Relay in the Finite Blocklength Regime

In this paper,we investigate the feasibility and performance of the covert communication with a spectrum sharing relay in the finite blocklength regime.Specifically,the relay opportunistically forwards the source's messages to the primary receiver or conveys the covert messages to its own receiver via the sharing spectrum,while the warden attempts to detect the transmission.First,we derive a lower bound on the covertness constraint,and the analytical expressions of both the primary average effective covert throughput(AECT)and sum AECT are presented by considering the overall decoding error performance.Then,we formulate two optimization problems to maximize the primary and sum AECT respectively by optimizing the blocklength and the transmit power at the source and the relay.Our examinations show that there exists an optimal blocklength to maximize the primary and sum AECT.Besides,it is revealed that,to maximize the primary AECT,the optimal transmit power of each hop increases as its channel quality deteriorates.Furthermore,in the optimization for maximizing the sum AECT,the optimal transmit power at the source equals to zero when the channel quality from relay to the secondary receiver is not weaker than that from relay to the primary receiver.

Preparation of porous Ta-10%Nb alloy scaffold and its in vitro biocompatibility evaluation using MC3T3-E1 cells

A highly porous Ta-10%Nb alloy was successfully prepared for tissue engineering via the methods of the sponge impregnation and sintering techniques.The porous Ta-10%Nb alloy offers the capability of processing a pore size of 300-600μm,a porosity of(68.0±0.41)%,and open porosity of(93.5±2.6)%.The alloy also shows desirable mechanical properties similar to those of cancellous bone with the elastic modulus and the comprehensive strength of(2.54±0.5)GPa and(83.43±2.5)MPa,respectively.The morphology of the pores in the porous Ta-Nb alloy shows a good interconnected three-dimension(3D)network open cell structure.It is also found that the rat MC3T3-E1 cell can well adhere,grow and proliferate on the porous Ta-Nb alloy.The interaction of the porous alloy on cells is attributed to its desirable pore structure,porosity and the great surface area.The advanced mechanical and biocompatible properties of the porous alloy indicate that this material has promising potential applications in tissue engineering.

Effects of charging rates on LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2)(NMC622)/graphite Li-ion cells

Enabling fast charging capability of lithium-ion battery is of great importance to widespread adoption of electric vehicles.Increasing the charging rates from state-of-the-art 2 C(30 min)to 6 C(10 min)requires deep understanding on the cell aging mechanism.In this study,400 mAh pouch cells are cycled at 1 C,4 C and 6 C charging rates with 1 C discharging rate.Capacity fading,cathode structural changes,Li inventory loss,electrolyte composition changes and Li plating on graphite electrodes are thoroughly studied by various characterization techniques.The rapid capacity fading in cells at 6 C charging rate is mainly due to Li inventory loss from cathode structure and metallic Li plating on graphite electrode at higher charging rate.Post-mortem analysis also revealed changes in electrolyte such as increased salt molarity and transesterification during fast charging.

Uterine rupture in patients with a history of multiple curettages:Two case reports

BACKGROUND Uterine rupture is a serious obstetric emergency,a severe event,and a serious threat to maternal and fetal life.It is a rare and not well characterized by the fact that multiple operations of uterine cavities contribute to uterine rupture during pregnancy.Atypical uterine rupture is easily misdiagnosed as other obstetric or surgical diseases.In current guidelines,abdominocentesis is a contraindication for late pregnancy.Therefore,the cases presented in this report provide new ideas for clinical diagnosis and treatment of uterine rupture.CASE SUMMARY Case 1,a 34-year-old woman(gravida 5,para 2),32 wk and 4 d of gestation,presented with acute upper abdominal pain for 8 h with nausea and vomiting.Computed tomography(CT)revealed pelvic and abdominal effusion.We extracted 3 mL unclotted blood from her abdominal cavity.An emergency caesarean section was performed.A uterine rupture was found,and the fimbrial portion of the left fallopian tube was completely adhered to the rupture.The prognosis of both the mother and the infant was good.Case 2,a 39-year-old woman(gravida 10,para 1)at 34 wk and 3 d of gestation complained of persistent lower abdominal pain for half a day.Her vital signs were normal.CT revealed a high probability of pelvic and abdominal hemoperitoneum.We extracted 4 mL dark red blood without coagulation.An emergency laparotomy was performed.Uterine rupture was identified during the operation.Postoperative course in both the mother and infant was uneventful.CONCLUSION For pregnant women in the second or the third trimester with persistent abdominal pain,abdominal effusion,fetal distress and even fetal death,the possibility of uterine rupture should be highly suspected.CT can identify acute abdominal surgical or gynecological and obstetric diseases.Abdominocentesis is helpful for diagnosing and clarifying the nature of effusion,but its clinical value need to be confirmed by further clinical studies.

Prevalence and impact of diabetes in patients with COVID-19 in China

BACKGROUND Coronavirus disease 2019(COVID-19)is an emerging infectious disease that has spread rapidly around the world.Previous studies have indicated that COVID-19 patients with diabetes are prone to having poor clinical outcomes.AIM To systematically evaluate the prevalence of diabetes among COVID-19 patients in China and its impact on clinical outcomes,including ICU admission,progression to severe cases,or death.METHODS We searched studies published in PubMed,Web of Science,and EMBASE from December 1,2019 to March 31,2020 to identify relevant observational study that investigated the prevalence of diabetes among COVID-19 patients or its impact on clinical outcomes.We used a random-effects or fixed-effects model to estimate the pooled prevalence of diabetes and risk ratio(RR)and its 95%confidence interval(CI)of diabetes on outcomes.Funnel plots were used to evaluate the publication bias and the heterogeneity was evaluated by I2 statistic.RESULTS Twenty-three eligible articles including 49564 COVID-19 patients(1573 with and 47991 without diabetes)were finally included.The pooled prevalence of diabetes was 10%(95%CI:7%-15%)in COVID-19 patients.In the subgroup analyses,the pooled prevalence of diabetes was higher in studies with patients aged>50 years(13%;95%CI:11%-16%)than in studies with patients aged≤50 years(7%;95%CI:6%-8%),in severe patients(17%;95%CI:14%-20%)than in non-severe patients(6%;95%CI:5%-8%),and in dead patients(30%;95%CI:13%-46%)than in survivors(8%;95%CI:2%-15%)(P<0.05 for all).Compared with patients without diabetes,the risk of severe cases was higher(RR=2.13,95%CI:1.76-2.56,I2=49%)in COVID-19 patients with diabetes.The risk of death was also higher in COVID-19 patients with diabetes(RR=3.16,95%CI:2.64-3.78,I2=34%).However,diabetes was not found to be significantly associated with admission to ICU(RR=1.16,95%CI:0.15-9.11).CONCLUSION Nearly one in ten COVID-19 patients have diabetes in China.Diabetes is associated with a higher risk of severe illness and death.The present study suggested that targeted early intervention is needed in COVID-19 patients with diabetes.

Efficacy of intravitreal injection of ranibizumab in the treatment of macular edema secondary to non-ischemic branch retinal vein occlusion

Objective: To observe the efficacy of intravitreal injection of ranibizumab in the treatment of macular edema(ME) secondary to non-ischemic branch retinal vein occlusion (BRVO). Methods: The clinical data of 27 patients (27 eyes) with macular edema secondary to non-ischemic BRVO were diagnosed by ophthalmology in Chongqing University Center Hospital from May 2018 to April 2019, selected as the experimental group, and 20 cases (20 eyes) of normal people as the control group. For the experimental group, before and after treatment, 1wk, 1mo, 2mo, 3mo and 6mo were used to observe the uncorrected visual acuity(UCVA),best corrected visual acuity (BCVA), intraocular pressure (IOP), central retinal thickness (CRT) macular center volume (MCV) and EN FACE images. Subjects in the normal control group were examined by optical coherence tomography (OCT) for CRT and CMV at 1wk, 1mo, 2mo, 3mo and 6mo on the day of and after enrollment. Results: The mean age of patients in the experimental group was (67.37±8.63) years old and the times of Intravitreal injection was (3.26 ±0.59) times. The successful rate of treatment was 85.19%. There was no significant difference in IOP between pre-treatment and 1wk, 1mo, 2mo, 3mo and 6mo (P > 0.05). 1wk, 1mo, 2mo, 3mo and 6mo BCVA were significantly higher than those before treatment (P < 0.0001). The levels of CRT and CMV at 1wk, 1mo, 2mo, 3mo and 6mo after treatment were significantly lower than those before treatment (P <0.01). Compared with the normal control group, the CRT and CMV of the experimental group before and after treatment showed statistically significant differences in 1wk, 1mo, 2mo and 3mo (P <0.05). There was no statistically significant difference in 6mo CRT and CMV after treatment (P>0.05). EN FACE showed that 1wk, 1mo, 2mo, 3mo and 6mo macular thickness decreased gradually, retinal edema subsided, cystoid changes disappeared, and the interlamellar structure of the ellipsoid zone gradually recovered after intravitreal injection of ranibizumab. Conclusion: Intravitreal injection of ranibizumab in the treatment of non-ischemic BRVO secondary ME has significant efficacy, EN FACE is an effective means to assess the severity, treatment and prognosis of patients.

Host immune response to infection with porcine circoviruses

Porcine circovirus type 2(PCV2),which serves as a major causative agent of PCV2-associated diseases and causes severe loss to the pig industry worldwide,can dysregulate the immune response and induce immunosuppression in PCV2-infected pigs.Similar to PCV2(porcine circovirus type 3(PCV3),a newly identified swine circovirus which might be closely associated with porcine dermatitis and nephropathy syndrome,reproductive disorder,and multisystemic inflammatoty responses,also interferes with host immune defense.Interaction between host immune system and PCVs is considered to be a crucial determinant of pathogenicity in pigs.Here,we sought to briefly discuss the current knowledge regarding the interaction of porcine circovirus type 2 and/or 3 with host immune cells and immune responses to better depict the viral immunomodulatory capacity,pathogenic mechanisms,and the future research direction in host immune responses to infection with PCV2 and PCV3.

Experts’Consensus on the Management of Respiratory Disease Syndemic

The global burden of respiratory diseases is a significant and increasing threat to individuals worldwide.In 2017,there were 544.9 million cases of chronic respiratory diseases,a 39.8%increase since 1990(1).These diseases were the third leading cause of global mortality in 2017,accounting for 7.0%of all deaths,an 18.0%increase compared to 1990.

Evaluation of COVID-19 outbreak prevention and control in Beijing using the emergency management theory

On April 29,2020,China entered a normalization stage of prevention and control.By December 2021,more than 40 outbreaks had occurred in China,which reflected the shortcomings of the pandemic prevention and control measures in China at that time.As the capital city of China,Beijing faces more pressure in epidemic prevention and control.We used the COVID-19 cluster containment evaluation indicators to determine the effects of prevention and control measures on four COVID-19 outbreaks in Beijing.After considering the specificity and operability of evaluation indicators and the availability of evaluation data,the evaluation system in our study consisted of six dimensions:epidemic prevention and control effect,discovery and detection ability,precision prevention and control capability,public protection effect,medical treatment and nosocomial infection prevention and control ability,and information release and public opinion response ability.The composite scores of the prevention and control effects of the Xinfadi,Shunyi,Daxing,and Ejina Banner–associated COVID-19 outbreaks in Beijing were 62,82,87,and 76,respectively.In the six dimensions,the epidemic prevention and control effect,discovery and detection ability,precision prevention and control capability,and public protection effect scores for the Xinfadi outbreak were lower than those for the Shunyi,Daxing and Ejina Banner–associated outbreaks.The medical treatment and nosocomial infection prevention and control ability scores for the outbreak associated with Ejina Banner were lower than those for the Xinfadi,Shunyi,and Daxing outbreaks.In managing cluster outbreaks,Beijing was able to detect index cases early enough to reduce the scale and duration of the outbreak and consistently release official information to reduce public panic,standardize the management of centralized quarantine sites to prevent cross-infection,adhere to the“dynamic COVID‐zero”strategy to accurately prevent and control outbreaks,reduce the societal influence of the pandemic,and coordinate the epidemic prevention and control and socio-economic development.

新时期健康中国建设中的医防协同:理论机制与政策演变

我国医防协同的实践由来已久,医防协同已成为我国新时期健康中国建设中全方位、全周期保障人民健康的重要途径。尽管我国的医防协同工作已经取得进展,但其相对割裂的现状并未发生根本性扭转。以此为背景,结合自2018年以来对不同地区、不同部门的现场调研以及现有研究,本文介绍了新时期我国医防协同的定义、政策演进过程及内涵,并设计了医防协同的理论机制模型,揭示了医疗服务体系与公共卫生体系整合的组织基础、服务供给内容及协同机制设计,为国内和国际整合型医疗卫生服务体系改革及治理提供理论基础、改革路径和中国经验。

Trends of SARS-CoV-2 Infection in Rural Area in Sentinel Community-Based Surveillance——China,December 2022 to January 2023

Introduction:In late 2022,a rapid transmission of Omicron variants of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)occurred throughout China.The purpose of this study was to provide the latest data and evaluate trends of SARS-CoV-2 infection in rural China among the community population.Methods:Data on SARS-CoV-2 infection among approximately 90,000 participants in rural China were collected by the National Sentinel Community-Based Surveillance(NSCS)system.Participants were tested for SARS-CoV-2 infection(defined as positive for SARS-CoV-2 nucleic acid or antigen)twice weekly from December 16,2022 to January 12,2023.The daily average of newly positive rate and its estimated daily percentage change were calculated to describe the national and regional trends of SARS-CoV-2 infection in rural China.Results:In rural China,the daily average new positive rate of SARS-CoV-2 infection peaked at 4.79%between December 20–22,2022 and then decreased to 0.57%between January 10–12,2023,with an average decrease of 29.95%per round.The peak of new SARS-CoV-2 infection was slightly earlier and lower in North China(5.28%between December 20–22,2022)than in South China(5.63%between December 23–26,2022),and then converged from December 30,2022 to January 2,2023.The peak of 6.09%occurred between December 20–22,2022 in eastern China,while the peak of 5.99%occurred later,between December 27–29,2022,in central China.Conclusions:Overall,the epidemic wave in rural China peaked between December 20–22,2022,and passed quickly following the optimization of prevention and control measures.Currently,SARSCoV-2 infection in community populations in rural China is sporadic.

Immunogenicity,effectiveness,and safety of COVID‑19 vaccines among children and adolescents aged 2–18 years:an updated systematic review and meta‑analysis

Background During the coronavirus disease 2019(COVID-19)pandemic,there is an urgent need for safe and effective COVID-19 vaccines to protect children and adolescents.This study aims to provide scientific evidence and recommendations for the application of COVID-19 vaccines in children and adolescents by analyzing the latest studies.Methods We systematically searched MEDLINE(accessed through PubMed),Embase,and Web of Science from January 1,2020,to October 8,2022.Eligible clinical trials,cohort studies,case‒control studies,and cross-sectional studies with extractable data were included in immunogenicity,effectiveness,and safety analyses.According to the heterogeneity,we chose a fixed-effect model(when I2≤50)or a random-effects model(when I2>50)to pool effect values.Results A total of 88 articles were included.The seroconversion rates after the first,second,and third doses of the vaccines were 86.10%,96.52%,and 99.87%,respectively.After the first and second doses,vaccine effectiveness(VE)against severe acute respiratory syndrome coronavirus 2 infection was 42.87%[95%confidence interval(CI)=27.09%–58.65%]and 63.33%(95%CI=52.09%–74.56%),respectively.After the first and second doses,VE against COVID-19 was 60.65%(95%CI=44.80%–76.50%)and 75.77%(95%CI=63.99%–87.56%),respectively.VE against hospitalization due to COVID-19 after the first and second doses was 72.74%(95%CI=51.48%–94.01%)and 82.78%(95%CI=75.78%–89.78%),respectively.The most common adverse events were injection site pain,fatigue/asthenia/tiredness,headache,myalgia/muscle pain,and chills.The incidence rate of myocarditis or pericarditis was 2.42/100,000 people.In addition,the subgroup analysis showed that children aged≤5 years had the lowest incidence of adverse events,and the incidence rate of adverse events was higher for mRNA vaccines than for inactivated vaccines.Conclusions COVID-19 vaccines have good immunogenicity,effectiveness,and safety among children and adolescents.We recommend that children and adolescents be vaccinated as soon as possible to protect them and slow the spread of COVID-19.

Trends of SARS-CoV-2 Infection in Sentinel Community-Based Surveillance After the Optimization of Prevention and Control Measures—China,December 2022-January 2023

Introduction:On December 7,2022,China implemented the“Ten New Measures”to optimize its prevention and control measures for coronavirus disease 2019(COVID-19).To provide the latest data after the optimization,we evaluated trends of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection among the community population in China.Methods:We utilized data from the National Sentinel Community-Based Surveillance(NSCS)system in China to assess trends of SARS-CoV-2 infection.NSCS is a national community-based surveillance cohort with 0.42 million participants from all 31 provincial-level administrative divisions(PLADs)and Xinjiang Production and Construction Corps(XPCC).Participants were tested for infection twice a week(a total of eight rounds)from December 16,2022 to January 12,2023.SARS-CoV-2 infection was defined as testing positive for SARS-CoV-2 nucleic acid or antigen.We calculated the daily average of newly positive rates of SARS-CoV-2 infection.Results:In this national cohort,the daily average newly positive rate of SARS-CoV-2 infection decreased from 4.13% in Round 1(December 16-19,2022)to 0.69% in Round 8(January 10-12,2023).The epidemic peak occurred in Round 2(December 20-22,2022).Similar trends were observed in urban areas(decreasing from 4.65% to 0.73%),rural areas(decreasing from 2.83% to 0.57%),the eastern region(decreasing from 4.18% to 0.67%),the central region(decreasing from 5.43% to 0.61%),and the western region(decreasing from 3.01%to 0.77%).Conclusions:NSCS data showed that the peak of SARS-CoV-2 infection in China had passed.SARSCoV-2 infection in community populations in China is currently at a low epidemic level.

Sentinel Community-Based Surveillance:An Innovative Mode of Proactive Surveillance on Infectious Disease

BACKGROUND Surveillance is a critical component of epidemiological and public health practice,playing a significant role in the prevention,control,and management of major public health risks(1).Historically,surveillance methods were primarily based on hospital data(e.g.,sentinel hospital monitoring for influenza)or specific populations[such as the human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS)population]for sentinel surveillance.

Analysis of the Practice of Community-Based Self-Sampling and Its Implication on Prevention and Control of Infectious Diseases—Fengtai District,Beijing Municipality,China,2022

Summary What is already known about this topic?So far,no descriptive analysis has been conducted on community residents with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)nucleic acid self-sampling in China.What is added by this report?This report found that self-sampling had a wide age and regional distribution,with the time from selfsampling to result-reporting typically taking less than one day.Additionally,self-sampling was found to save a considerable amount of manpower and medical resources compared to regular sampling.What are the implications for public health practice?The experience of prevention and control measures during the coronavirus disease 2019(COVID-19)pandemic has provided a reference for the prevention and control of other infectious diseases through selfsampling.

Survey of Residents’ Satisfaction with the Environmental Sanitation of Key Public Places Under the Background of National Healthy City-China, 2021

National healthy city establishment is an urban construction activity with Chinese characteristics.As an essential part of establishing national healthy cities,environmental sanitation covers many environmental hygiene-related issues.Among them,public place sanitation has been the focus and difficulty in China for many years,especially in key public places(small restaurants,small“internet cafes,”small hairdressers,small dance halls,small hotels,and small bathrooms),which are ubiquitous.

Medical Consultations Option and Influencing Factors for SARS-CoV-2 Infected Individuals-Beijing Municipality,China,December 2022

Summary What is already known about this topic?In December 2022,China revised its epidemic prevention and control strategy,leading to an increase in coronavirus disease 2019(COVID-19)cases and a peak in medical consultations.Government departments implemented relevant policies to coordinate and allocate medical resources throughout China.However,there is a scarcity of research on the status of medical consultations and the factors influencing them.

Trends of SARS-CoV-2 Infection Among Couriers in Risky Business After the Optimization of Prevention and Control Measures——China,December 2022 to January 2023

Introduction:On December 7,2022,China implemented“Ten New Measures”to optimize prevention and control measures for coronavirus disease 2019(COVID-19).The purpose of this study was to evaluate the national and regional trends of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection among couriers in China from December 2022 to January 2023.Methods:Data from the National Sentinel Community-based Surveillance in China was utilized,including participants from 31 provincial-level administrative divisions and Xinjiang Production and Construction Corps.Participants were tested for SARS-CoV-2 infection twice a week from December 16,2022 to January 12,2023.Infection was defined as a positive result for SARS-CoV-2 nucleic acid or antigen.The daily average newly positive rate of SARSCoV-2 infection and the estimated daily percentage change(EDPC)were calculated.Results:In this cohort,8 rounds of data were collected.The daily average newly positive rate of SARS-CoV-2 infection decreased from 4.99%in Round 1 to 0.41%in Round 8,with an EDPC of−33.0%.Similar trends of the positive rate were also observed in the eastern(EDPC:−27.7%),central(EDPC:−38.0%)and western regions(EDPC:−25.5%).Couriers and community population showed a similar temporal trend,with the peak daily average newly positive rate of couriers being higher than that of community population.After Round 2,the daily average newly positive rate of couriers decreased sharply,becoming lower than that of community population in the same period.Conclusions:The peak of SARS-CoV-2 infection among couriers in China has passed.As couriers are a key population for SARS-CoV-2 infection,they should be monitored continuously.