The SARS-CoV-2 virus,particularly the Omicron BA.2 variant,led to a significant surge in Shanghai,2022.However,the viral load dynamic in Omicron infections with varying clinical severities remain unclear.This prospect...The SARS-CoV-2 virus,particularly the Omicron BA.2 variant,led to a significant surge in Shanghai,2022.However,the viral load dynamic in Omicron infections with varying clinical severities remain unclear.This prospective cohort included 48,830 hospitalized coronavirus disease 2019(COVID-19)patients across three hospitals in Shanghai,China,between 23 March and 15 May,2022.Systematic nucleic acid testing was performed using RT-PCR Cycle threshold(Ct)value as a proxy of viral load.We analyzed the kinetic characteristics of viral shedding by clinical severity and identified associated risk factors.The study comprised 31.06%asymptomatic cases,67.66%mild-moderate cases,1.00%severe cases,0.29%critical and fatal cases.Upon admission,57%of patients tested positive,with peak viral load observed at 4 days(median Ct value 27.5),followed by a decrease and an average viral shedding time(VST)of 6.1 days(Interquartile range,4.0–8.8 days).Although viral load exhibited variation by age and clinical severity,peak Ct values occurred at similar times.Unvaccinated status,age exceeding 60,and comorbidities including hypertension,renal issues kidney dialysis and kidney transplantation,neurological disorders,rheumatism,and psychotic conditions were found to correlate with elevated peak viral load and extended VST.Asymptomatic cases demonstrated a 40%likelihood of contagiousness within 6 days of detection,while mild-moderate and severe cases exhibited post-symptom resolution infectious probabilities of 27%and over 50%,respectively.These findings revealed that the initial Ct values serve as a predictive indicator of severe outcomes.Unvaccinated elderly individuals with particular comorbidities are at high-risk for elevated viral load and prolonged VST.展开更多
Introduction Social contact patterns significantly influence the transmission dynamics of respiratory pathogens.Previous surveys have quantified human social contact patterns,yielding heterogeneous results across diff...Introduction Social contact patterns significantly influence the transmission dynamics of respiratory pathogens.Previous surveys have quantified human social contact patterns,yielding heterogeneous results across different locations.However,significant gaps remain in understanding social contact patterns in rural areas of China.Methods We conducted a pioneering study to quantify social contact patterns in Anhua County,Hunan Province,China,from June to October 2021,when there were minimal coronavirus disease-related restrictions in the area.Additionally,we simulated the epidemics under different assumptions regarding the relative transmission risks of various contact types(e.g.,indoor versus outdoor,and physical versus non-physical).Results Participants reported an average of 12.0 contacts per day(95%confidence interval:11.3–12.6),with a significantly higher number of indoor contacts compared to outdoor contacts.The number of contacts was associated with various socio-demographic characteristics,including age,education level,income,household size,and travel patterns.Contact patterns were assortative by age and varied based on the type of contact(e.g.,physical versus non-physical).The reproduction number,daily incidence,and infection attack rate of simulated epidemics were remarkably stable.Discussion We found many intergenerational households and contacts that pose challenges in preventing and controlling infections among the elderly in rural China.Our study also underscores the importance of integrating various types of contact pattern data into epidemiological models and provides guidance to public health authorities and other major stakeholders in preparing and responding to infectious disease threats in rural China.展开更多
Background:China is facing substantial risks of imported coronavirus disease 2019(COVID-19)cases and a domestic resurgence in the long run,and COVID-19 vaccination is expected to be the long-lasting solution to end th...Background:China is facing substantial risks of imported coronavirus disease 2019(COVID-19)cases and a domestic resurgence in the long run,and COVID-19 vaccination is expected to be the long-lasting solution to end the pandemic.We aim to estimate the size of the target population for COVID-19 vaccination at the provincial level in the mainland of China,and summarize the current progress of vaccination programs,which could support local governments in the timely determination and adjustment of vaccination policies and promotional measures.Methods:We conducted a descriptive study of the entire population in the mainland of China,between December 2020 and August 2021.By extracting provincial-stratifed data from publicly available sources,we estimated the size of priority target groups for vaccination programs,and further characterized the ongoing vaccination program at the provincial level,including the total doses administered,the coverage rate,and the vaccination capacity needed to achieve the target coverage of 80%by the end of 2021.We used R(version 4.1.0)to complete the descriptive statistics.Results:The size of the target population shows large diferences among provinces,ranging from 3.4 million to 108.4 million.As of 31 August,2021,the speed of vaccine roll-out difers considerably as well,with the highest coverage occurring in Beijing and Shanghai,where 88.5%and 79.1%of the population has been fully vaccinated,respectively.In 22 of 31 provincial-level administrative divisions(PLADs),more than 70%of the population was administered at least one dose by August.With the current vaccination capacity,the target of 80%coverage could be achieved by 2021 in 28 PLADs.Conclusions:Disparities exist in the target population size and vaccination progress across provinces in the mainland of China.China has made great strides in the vaccination speed since roll-out,and could basically achieve the targeted vaccine coverage.展开更多
Summary What is already known about this topic?Previous studies have explored the spatial transmission patterns of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and have assessed the associated risk facto...Summary What is already known about this topic?Previous studies have explored the spatial transmission patterns of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and have assessed the associated risk factors.However,none of these studies have quantitatively described the spatiotemporal transmission patterns and risk factors for Omicron BA.2 at the micro(within-city)scale.展开更多
Monitoring changes in the epidemiologic features between different severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)variants is key to understanding the evolution of viral fitness in the host population.Here...Monitoring changes in the epidemiologic features between different severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)variants is key to understanding the evolution of viral fitness in the host population.Here,we analyzed a successfully contained local outbreak of the Delta variant that took place in Hunan,China,in July–August,2021.Detailed data on SARS-CoV-2 infections and their contacts were collected during the outbreak.By leveraging these data,we estimated key epidemiological parameters,including the incubation period,serial interval,and generation time.We constructed a generalized linear mixed-effects model(GLMM)to quantify risk factors for Delta infection and transmission.Between July 28 and August 15,2021,a total of 129 infections and their 2,118 close contacts were identified during the outbreak in Hunan Province.展开更多
基金financial support from the Key Program of the National Natural Science Foundation of China(82130093)Wenhong Zhang,Juanjuan Zhang acknowledge financial support from Shanghai Municipal Science and Technology Major Project(HS2021SHZX001)+2 种基金Wenhong Zhang acknowledges financial support from the Key Program of the National Natural Science Foundation of China(82161138018 and 82041010)Shanghai Science and Technology Committee(20dz2260100,20Z11901100)Shanghai Hospital Development Center(SHDC2020 CR5010-002).
文摘The SARS-CoV-2 virus,particularly the Omicron BA.2 variant,led to a significant surge in Shanghai,2022.However,the viral load dynamic in Omicron infections with varying clinical severities remain unclear.This prospective cohort included 48,830 hospitalized coronavirus disease 2019(COVID-19)patients across three hospitals in Shanghai,China,between 23 March and 15 May,2022.Systematic nucleic acid testing was performed using RT-PCR Cycle threshold(Ct)value as a proxy of viral load.We analyzed the kinetic characteristics of viral shedding by clinical severity and identified associated risk factors.The study comprised 31.06%asymptomatic cases,67.66%mild-moderate cases,1.00%severe cases,0.29%critical and fatal cases.Upon admission,57%of patients tested positive,with peak viral load observed at 4 days(median Ct value 27.5),followed by a decrease and an average viral shedding time(VST)of 6.1 days(Interquartile range,4.0–8.8 days).Although viral load exhibited variation by age and clinical severity,peak Ct values occurred at similar times.Unvaccinated status,age exceeding 60,and comorbidities including hypertension,renal issues kidney dialysis and kidney transplantation,neurological disorders,rheumatism,and psychotic conditions were found to correlate with elevated peak viral load and extended VST.Asymptomatic cases demonstrated a 40%likelihood of contagiousness within 6 days of detection,while mild-moderate and severe cases exhibited post-symptom resolution infectious probabilities of 27%and over 50%,respectively.These findings revealed that the initial Ct values serve as a predictive indicator of severe outcomes.Unvaccinated elderly individuals with particular comorbidities are at high-risk for elevated viral load and prolonged VST.
基金funded by the Shanghai Municipal Science and Technology Major Project(ZD2021CY001)the National Institute for Health Research(NIHR)(16/137/109)using UK aid from the UK Government to support global health research+2 种基金the Key Program of the National Natural Science Foundation of China(82130093)the National Natural Science Foundation of China(92369118 and 82304202)Shanghai Rising-Star Program(No.22QA1402300).
文摘Introduction Social contact patterns significantly influence the transmission dynamics of respiratory pathogens.Previous surveys have quantified human social contact patterns,yielding heterogeneous results across different locations.However,significant gaps remain in understanding social contact patterns in rural areas of China.Methods We conducted a pioneering study to quantify social contact patterns in Anhua County,Hunan Province,China,from June to October 2021,when there were minimal coronavirus disease-related restrictions in the area.Additionally,we simulated the epidemics under different assumptions regarding the relative transmission risks of various contact types(e.g.,indoor versus outdoor,and physical versus non-physical).Results Participants reported an average of 12.0 contacts per day(95%confidence interval:11.3–12.6),with a significantly higher number of indoor contacts compared to outdoor contacts.The number of contacts was associated with various socio-demographic characteristics,including age,education level,income,household size,and travel patterns.Contact patterns were assortative by age and varied based on the type of contact(e.g.,physical versus non-physical).The reproduction number,daily incidence,and infection attack rate of simulated epidemics were remarkably stable.Discussion We found many intergenerational households and contacts that pose challenges in preventing and controlling infections among the elderly in rural China.Our study also underscores the importance of integrating various types of contact pattern data into epidemiological models and provides guidance to public health authorities and other major stakeholders in preparing and responding to infectious disease threats in rural China.
文摘Background:China is facing substantial risks of imported coronavirus disease 2019(COVID-19)cases and a domestic resurgence in the long run,and COVID-19 vaccination is expected to be the long-lasting solution to end the pandemic.We aim to estimate the size of the target population for COVID-19 vaccination at the provincial level in the mainland of China,and summarize the current progress of vaccination programs,which could support local governments in the timely determination and adjustment of vaccination policies and promotional measures.Methods:We conducted a descriptive study of the entire population in the mainland of China,between December 2020 and August 2021.By extracting provincial-stratifed data from publicly available sources,we estimated the size of priority target groups for vaccination programs,and further characterized the ongoing vaccination program at the provincial level,including the total doses administered,the coverage rate,and the vaccination capacity needed to achieve the target coverage of 80%by the end of 2021.We used R(version 4.1.0)to complete the descriptive statistics.Results:The size of the target population shows large diferences among provinces,ranging from 3.4 million to 108.4 million.As of 31 August,2021,the speed of vaccine roll-out difers considerably as well,with the highest coverage occurring in Beijing and Shanghai,where 88.5%and 79.1%of the population has been fully vaccinated,respectively.In 22 of 31 provincial-level administrative divisions(PLADs),more than 70%of the population was administered at least one dose by August.With the current vaccination capacity,the target of 80%coverage could be achieved by 2021 in 28 PLADs.Conclusions:Disparities exist in the target population size and vaccination progress across provinces in the mainland of China.China has made great strides in the vaccination speed since roll-out,and could basically achieve the targeted vaccine coverage.
基金Supported by the Key Program of the National Natural Science Foundation of China(82130093 to H.Y.)Shanghai Rising-Star Program(22QA1402300 to J.Z.).
文摘Summary What is already known about this topic?Previous studies have explored the spatial transmission patterns of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and have assessed the associated risk factors.However,none of these studies have quantitatively described the spatiotemporal transmission patterns and risk factors for Omicron BA.2 at the micro(within-city)scale.
基金Supported by grants from the Key Program of the National Natural Science Foundation of China(82130093)Shanghai Municipal Science and Technology Major Project(ZD2021CY001)+1 种基金Hunan Provincial Innovative Construction Special Fund:Emergency response to COVID-19 outbreak(No.2020SK3012)Chinese Academy of Medical Sciences Coronavirus Disease 2019 Science and Technology Research Project in 2020(No.2020HY320003)。
文摘Monitoring changes in the epidemiologic features between different severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)variants is key to understanding the evolution of viral fitness in the host population.Here,we analyzed a successfully contained local outbreak of the Delta variant that took place in Hunan,China,in July–August,2021.Detailed data on SARS-CoV-2 infections and their contacts were collected during the outbreak.By leveraging these data,we estimated key epidemiological parameters,including the incubation period,serial interval,and generation time.We constructed a generalized linear mixed-effects model(GLMM)to quantify risk factors for Delta infection and transmission.Between July 28 and August 15,2021,a total of 129 infections and their 2,118 close contacts were identified during the outbreak in Hunan Province.
