After the policy adjustment,China no longer carries out COVID-19 PCR testing for all people,and antigen testing has become the main way to detect and manage infectious sources.We developed a dynamic model to evaluate ...After the policy adjustment,China no longer carries out COVID-19 PCR testing for all people,and antigen testing has become the main way to detect and manage infectious sources.We developed a dynamic model to evaluate and compare the effects between PCR and antigen testing for controlling the pandemic.Due to the increase of contact degree,the peak reduction effect of PCR testing in population is lower than that of antigen testing.Even if it was only 20%of people isolated at home after antigen testing,the peak of the epidemic could be reduced by 9.46%.If the proportion of antigen testing is further increased to 80%,the peak of the pandemic can be reduced by 31.41%.Antigen testing performed better effects in school(reduction proportion 29.27%)and community(29.34%)than in workplace(27.75%).Therefore,we recommend that antigen testing in the popu-lation should be encouraged during the pandemic,and home isolation of infected persons should be advocated,especially in crowded places.To improve the availability of antigen,the testing proportion should be further enhanced.展开更多
The number of coronavirus disease 2019(COVID-19)cases continues to surge,overwhelming healthcare systems and causing excess mortality in many countries.Testing of infectious populations remains a key strategy to conta...The number of coronavirus disease 2019(COVID-19)cases continues to surge,overwhelming healthcare systems and causing excess mortality in many countries.Testing of infectious populations remains a key strategy to contain the COVID-19 outbreak,delay the exponential spread of the disease,and flatten the epidemic curve.Using the Omicron variant outbreak as a background,this study aimed to evaluate the effectiveness of testing strategies with different test combinations and frequencies,analyze the factors associated with testing effectiveness,and optimize testing strategies based on these influencing factors.We developed a stochastic,agent-based,discrete-time susceptible–latent–infectious–recovered model simulating a community to estimate the association between three levels of testing strategies and COVID-19 transmission.Antigen testing and its combination strategies were more efficient than polymerase chain reaction(PCR)-related strategies.Antigen testing also showed better performance in reducing the demand for hospital beds and intensive care unit beds.The delay in the turnaround time of test results had a more significant impact on the efficiency of the testing strategy compared to the detection limit of viral load and detection-related contacts.The main advantage of antigen testing strategies is the short turnaround time,which is also a critical factor to be optimized to improve PCR strategies.After modifying the turnaround time,the strategies with less frequent testing were comparable to daily testing.The choice of testing strategy requires consideration of containment goals,test efficacy,community prevalence,and economic factors.This study provides evidence for the selection and optimization of testing strategies in the post-pandemic era and provides guidance for optimizing healthcare resources.展开更多
This study aims to improve control schemes for COVID-19 by a numerical model with estimation of parameters.We established a multi-level and multi-objective nonlinear SEIDR model to simulate the virus transmission.The ...This study aims to improve control schemes for COVID-19 by a numerical model with estimation of parameters.We established a multi-level and multi-objective nonlinear SEIDR model to simulate the virus transmission.The early spread in Japan was adopted as a case study.The first 96 days since the infection were divided into five stages with parameters estimated.Then,we analyzed the trend of the parameter value,age structure ratio,and the defined PCR test index(standardization of the scale of PCR tests).It was discovered that the self-healing rate and confirmed rate were linear with the age structure ratio and the PCR test index using the stepwise regression method.The transmission rates were related to the age structure ratio,PCR test index,and isolation efficiency.Both isolation measures and PCR test medical screening can effectively reduce the number of infected cases based on the simulation results.However,the strategy of increasing PCR test medical screening would encountered a bottleneck effect on the virus control when the index reached 0.3.The effectiveness of the policy would decrease and the basic reproduction number reached the extreme value at 0.6.This study gave a feasible combination for isolation and PCR test by simulation.The isolation intensity could be adjusted to compensate the insufficiency of PCR test to control the pandemic.展开更多
In recent years, owing to abuse of antibiotics, extensive use of antitumor drugs and immunosuppressive agents and other reasons, an increasing number of people suffered from fungal infection. In this situation, resear...In recent years, owing to abuse of antibiotics, extensive use of antitumor drugs and immunosuppressive agents and other reasons, an increasing number of people suffered from fungal infection. In this situation, researchers proposed new diagnosis methods,such as G test, galactomannan (GM) test, and polymerase chain reaction (PCR). G test is simple, quick, and highly sensitive and can detect multiple fungi; however, it cannot distinguish fungal types and may result in false positive and false negative results. GM test is less time consuming and feature highly positive detection rates but can simply be used in inspection of invasive aspergillosis. However, optimal positive critical values of GM test remain controversial. PCR is currently one of the fastest methods but is not formally used in clinical practice because of its lack of standardized operation and evaluation criteria.This study reviews the above three methods with the aim of discovering and summarizing their advantages and disadvantages to facilitate research and development of new diagnosis methods.展开更多
Introduction:Dengue fever represents a significant public health challenge in tropical and subtropical regions worldwide,including China.This study aims to enhance early dengue detection and diagnosis by evaluating he...Introduction:Dengue fever represents a significant public health challenge in tropical and subtropical regions worldwide,including China.This study aims to enhance early dengue detection and diagnosis by evaluating healthcare facilities’diagnostic capacity and clinicians’awareness.Methods:In June 2024,surveys were conducted in 11 secondary and higher-level hospitals and 11 community health centers.Data from facilities evaluations and clinician questionnaires were analyzed using chi-square tests and logistic regression.Results:Secondary and higher-level hospitals demonstrated more robust dengue-related institutionbuilding but exhibited deficiencies in suspected case screening and public awareness efforts.Additionally,polymerase chain reaction(PCR)testing capacity was limited to one higher-level hospital,and nonstructural protein 1(NS1)testing costs were high in secondary and higher-level hospitals,with varying reimbursement rates due to different insurance types and institutional levels.Significant disparities in diagnostic awareness were found across hospital levels,departments,ages,and professional titles(P<0.05).The regression analysis shows that education can significantly enhance diagnostic awareness[odds ratio(OR)=13.780,95%confidence interval(CI):2.937,64.650].Conclusions:These findings underscore the need for dynamically adjust dengue testing strategies at different epidemic stages and improve NS1 testing cost reimbursement.Also,there should be more efforts in enhancing PCR testing in healthcare facilities and promoting health education.展开更多
At the end of 2021,with the rapid escalation of COVID19 cases due to the Omicron variant,testing centers in Canada were overwhelmed.To alleviate the pressure on the PCR testing capacity,many provinces implemented new ...At the end of 2021,with the rapid escalation of COVID19 cases due to the Omicron variant,testing centers in Canada were overwhelmed.To alleviate the pressure on the PCR testing capacity,many provinces implemented new strategies that promote self testing and adjust the eligibility for PCR tests,making the count of new cases underreported.We designed a novel compartmental model which captures the new testing guidelines,social behaviours,booster vaccines campaign and features of the newest variant Omicron.To better describe the testing eligibility,we considered the population divided into high risk and non-highrisk settings.The model is calibrated using data from January 1 to February 9,2022,on cases and severe outcomes in Canada,the province of Ontario and City of Toronto.We conduct analyses on the impact of PCR testing capacity,self testing,different levels of reopening and vaccination coverage on cases and severe outcomes.Our results show that the total number of cases in Canada,Ontario and Toronto are 2.34(95%CI:1.22e3.38),2.20(95%CI:1.15e3.72),and 1.97(95%CI:1.13e3.41),times larger than reported cases,respectively.The current testing strategy is efficient if partial restrictions,such as limited capacity in public spaces,are implemented.Allowing more people to have access to PCR reduces the daily cases and severe outcomes;however,if PCR test capacity is insufficient,then it is important to promote self testing.Also,we found that reopening to a pre-pandemic level will lead to a resurgence of the infections,peaking in late March or April 2022.Vaccination and adherence to isolation protocols are important supports to the testing policies to mitigate any possible spread of the virus.展开更多
基金supported by the National Key Research and Development Program of China (2021YFC2301604)Guiding projects of Science and Technology Program in Fujian Province (2019D014).
文摘After the policy adjustment,China no longer carries out COVID-19 PCR testing for all people,and antigen testing has become the main way to detect and manage infectious sources.We developed a dynamic model to evaluate and compare the effects between PCR and antigen testing for controlling the pandemic.Due to the increase of contact degree,the peak reduction effect of PCR testing in population is lower than that of antigen testing.Even if it was only 20%of people isolated at home after antigen testing,the peak of the epidemic could be reduced by 9.46%.If the proportion of antigen testing is further increased to 80%,the peak of the pandemic can be reduced by 31.41%.Antigen testing performed better effects in school(reduction proportion 29.27%)and community(29.34%)than in workplace(27.75%).Therefore,we recommend that antigen testing in the popu-lation should be encouraged during the pandemic,and home isolation of infected persons should be advocated,especially in crowded places.To improve the availability of antigen,the testing proportion should be further enhanced.
基金supported by grants from the Chinese Academy of Medical Sciences(CAMS)Innovation Fund for Medical Sciences(2020-I2M-1-001 and 2021-I2M-1-044)。
文摘The number of coronavirus disease 2019(COVID-19)cases continues to surge,overwhelming healthcare systems and causing excess mortality in many countries.Testing of infectious populations remains a key strategy to contain the COVID-19 outbreak,delay the exponential spread of the disease,and flatten the epidemic curve.Using the Omicron variant outbreak as a background,this study aimed to evaluate the effectiveness of testing strategies with different test combinations and frequencies,analyze the factors associated with testing effectiveness,and optimize testing strategies based on these influencing factors.We developed a stochastic,agent-based,discrete-time susceptible–latent–infectious–recovered model simulating a community to estimate the association between three levels of testing strategies and COVID-19 transmission.Antigen testing and its combination strategies were more efficient than polymerase chain reaction(PCR)-related strategies.Antigen testing also showed better performance in reducing the demand for hospital beds and intensive care unit beds.The delay in the turnaround time of test results had a more significant impact on the efficiency of the testing strategy compared to the detection limit of viral load and detection-related contacts.The main advantage of antigen testing strategies is the short turnaround time,which is also a critical factor to be optimized to improve PCR strategies.After modifying the turnaround time,the strategies with less frequent testing were comparable to daily testing.The choice of testing strategy requires consideration of containment goals,test efficacy,community prevalence,and economic factors.This study provides evidence for the selection and optimization of testing strategies in the post-pandemic era and provides guidance for optimizing healthcare resources.
基金National Natural Science Foundation of China under Grant Nos.61803152,31920103016,and 11871475Doctoral Start-Up Foundation of Hunan Normal University under Grant No.0531120-3827Hunan Provincial Education Department under Grant No.HNKCSZ-2020-0813.
文摘This study aims to improve control schemes for COVID-19 by a numerical model with estimation of parameters.We established a multi-level and multi-objective nonlinear SEIDR model to simulate the virus transmission.The early spread in Japan was adopted as a case study.The first 96 days since the infection were divided into five stages with parameters estimated.Then,we analyzed the trend of the parameter value,age structure ratio,and the defined PCR test index(standardization of the scale of PCR tests).It was discovered that the self-healing rate and confirmed rate were linear with the age structure ratio and the PCR test index using the stepwise regression method.The transmission rates were related to the age structure ratio,PCR test index,and isolation efficiency.Both isolation measures and PCR test medical screening can effectively reduce the number of infected cases based on the simulation results.However,the strategy of increasing PCR test medical screening would encountered a bottleneck effect on the virus control when the index reached 0.3.The effectiveness of the policy would decrease and the basic reproduction number reached the extreme value at 0.6.This study gave a feasible combination for isolation and PCR test by simulation.The isolation intensity could be adjusted to compensate the insufficiency of PCR test to control the pandemic.
文摘In recent years, owing to abuse of antibiotics, extensive use of antitumor drugs and immunosuppressive agents and other reasons, an increasing number of people suffered from fungal infection. In this situation, researchers proposed new diagnosis methods,such as G test, galactomannan (GM) test, and polymerase chain reaction (PCR). G test is simple, quick, and highly sensitive and can detect multiple fungi; however, it cannot distinguish fungal types and may result in false positive and false negative results. GM test is less time consuming and feature highly positive detection rates but can simply be used in inspection of invasive aspergillosis. However, optimal positive critical values of GM test remain controversial. PCR is currently one of the fastest methods but is not formally used in clinical practice because of its lack of standardized operation and evaluation criteria.This study reviews the above three methods with the aim of discovering and summarizing their advantages and disadvantages to facilitate research and development of new diagnosis methods.
基金supported by the National Key Research and Development Program of China(grant number 2024YFC2311500)The Key Project of Medicine Discipline of Guangzhou(No.2025-2027-11)General Guidance Project for Health Science and Technology in Guangzhou(No.20231A011069).
文摘Introduction:Dengue fever represents a significant public health challenge in tropical and subtropical regions worldwide,including China.This study aims to enhance early dengue detection and diagnosis by evaluating healthcare facilities’diagnostic capacity and clinicians’awareness.Methods:In June 2024,surveys were conducted in 11 secondary and higher-level hospitals and 11 community health centers.Data from facilities evaluations and clinician questionnaires were analyzed using chi-square tests and logistic regression.Results:Secondary and higher-level hospitals demonstrated more robust dengue-related institutionbuilding but exhibited deficiencies in suspected case screening and public awareness efforts.Additionally,polymerase chain reaction(PCR)testing capacity was limited to one higher-level hospital,and nonstructural protein 1(NS1)testing costs were high in secondary and higher-level hospitals,with varying reimbursement rates due to different insurance types and institutional levels.Significant disparities in diagnostic awareness were found across hospital levels,departments,ages,and professional titles(P<0.05).The regression analysis shows that education can significantly enhance diagnostic awareness[odds ratio(OR)=13.780,95%confidence interval(CI):2.937,64.650].Conclusions:These findings underscore the need for dynamically adjust dengue testing strategies at different epidemic stages and improve NS1 testing cost reimbursement.Also,there should be more efforts in enhancing PCR testing in healthcare facilities and promoting health education.
基金supported by the Natural Sciences and Engineering Research Council of Canada and Public Health Agency of Canada OMNI one health modelling network for the Emerging Infectious Diseases Modelling Initiativethe Canadian Institutes of Health Research(CIHR)Canadian COVID-19 Math Modelling Task Force,and by York Research Chair Program.
文摘At the end of 2021,with the rapid escalation of COVID19 cases due to the Omicron variant,testing centers in Canada were overwhelmed.To alleviate the pressure on the PCR testing capacity,many provinces implemented new strategies that promote self testing and adjust the eligibility for PCR tests,making the count of new cases underreported.We designed a novel compartmental model which captures the new testing guidelines,social behaviours,booster vaccines campaign and features of the newest variant Omicron.To better describe the testing eligibility,we considered the population divided into high risk and non-highrisk settings.The model is calibrated using data from January 1 to February 9,2022,on cases and severe outcomes in Canada,the province of Ontario and City of Toronto.We conduct analyses on the impact of PCR testing capacity,self testing,different levels of reopening and vaccination coverage on cases and severe outcomes.Our results show that the total number of cases in Canada,Ontario and Toronto are 2.34(95%CI:1.22e3.38),2.20(95%CI:1.15e3.72),and 1.97(95%CI:1.13e3.41),times larger than reported cases,respectively.The current testing strategy is efficient if partial restrictions,such as limited capacity in public spaces,are implemented.Allowing more people to have access to PCR reduces the daily cases and severe outcomes;however,if PCR test capacity is insufficient,then it is important to promote self testing.Also,we found that reopening to a pre-pandemic level will lead to a resurgence of the infections,peaking in late March or April 2022.Vaccination and adherence to isolation protocols are important supports to the testing policies to mitigate any possible spread of the virus.
