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The current outbreak of novel coronavirus disease 2019 (COVID-19) is already causing a serious disease burden worldwide, this paper analyzed data of a delta variant Covid-19 outbreak in Hunan, China, and proposed an optimal dose-wise dynamical vaccinating process based on local contact pattern and vaccine coverage that minimize the accumulative cases in a certain future time interval. The optimized result requires an immediate vaccination to that none vaccinated at age group 30 to 39, which is coherent to the prevailing strategies. The dose-wise optimal vaccinating process can be directive for countries or regions where vaccines are not abundant. We recommend that vaccination should be further intensified to increase the coverage of booster shots, thus effectively reducing the spread of COVID-19.
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Objective To analyze the spatial and temporal characteristics of hand, foot and mouth disease (HFMD) in Hunan Province from 2016 to 2020. Methods The data of HFMD in Hunan Province from 2016 to 2020 were collected from China's Disease Prevention and Control Information System. HFMD spatial autocorrelation analysis was conducted by ArcGIS 10.2 software at county level, and spatial-temporal scan statistical analysis was performed by SaTScan 9.7 software. Results A total of 714 157 cases was reported in Hunan Province during 2016-2020, with an average annual incidence rate of 208.36/100 000. Global spatial autocorrelation showed that HFMD had a positive spatial correlation on the county scale in Hunan Province during this period. Local spatial autocorrelation indicated that the hot spots were mainly concentrated in the north of central Hunan, the east of central Hunan and the west of Hunan. Spatial-temporal scanning analysis revealed the first class clusters (RR = 6.65, P< 0.001) covering 34 counties in northern and central Hunan, mainly distributed in Yueyang City, Changsha City, Zhuzhou City, Yiyang City and Xiangtan City from May 2018 to June, and the second class clusters (RR = 3.02, P < 0.001) covering 40 counties in western Hunan and central and southwest Hunan from April 2016 to June 2016. Conclusion HFMD incidence exhibits seasonal and regional characteristics in Hunan Province. The prevention and control of HFMD should be guided by combining the characteristics of spatial-temporal clustering.
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A long-standing question in infectious disease dynamics is the role of transmission heterogeneities, particularly those driven by demography, behavior and interventions. Here we characterize transmission risk between 1,178 SARS-CoV-2 infected individuals and their 15,648 close contacts based on detailed contact tracing data from Hunan, China. We find that 80% of secondary transmissions can be traced back to 14% of SARS-CoV-2 infections, indicating substantial transmission heterogeneities. Regression analysis suggests a marked gradient of transmission risk scales positively with the duration of exposure and the closeness of social interactions, after adjusted for demographic and clinical factors. Population-level physical distancing measures confine transmission to families and households; while case isolation and contact quarantine reduce transmission in all settings. Adjusted for interventions, the reconstructed infectiousness profile of a typical SARS-CoV-2 infection peaks just before symptom presentation, with ~50% of transmission occurring in the pre-symptomatic phase. Modelling results indicate that achieving SARS-CoV-2 control would require the synergistic efforts of case isolation, contact quarantine, and population-level physical distancing measures, owing to the particular transmission kinetics of this virus.
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BackgroundSeveral parameters driving the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remain unclear, including age-specific differences in infectivity and susceptibility, and the contribution of inapparent infections to transmission. Robust estimates of key time-to-event distributions remain scarce as well. MethodsWe collected individual records for 1,178 SARS-CoV-2 infected individuals and their 15,648 contacts identified by contact tracing and monitoring over the period from January 13 to April 02, 2020 in Hunan Province, China. We provide descriptive statistics of the characteristics of cases and their close contacts; we fitted distributions to time-to-key-events distributions and infectiousness profile over time; and we used generalized linear mixed model to estimate risk factors for susceptibility and transmissibility of SARS-CoV-2. ResultsWe estimated the mean serial interval at 5.5 days (95%CI -5.0, 19.9) and the mean generation time at 5.5 days (95%CI 1.7, 11.6). The infectiousness was estimated to peak 1.8 days before symptom onset, with 95% of transmission events occurring between 7.6 days before and 7.3 days after the date of symptom onset. The proportion of pre-symptomatic transmission was estimated to be 62.5%. We estimated that at least 3.5% of cases were generated asymptomatic individuals. SARS-CoV-2 transmissibility was not significantly different between working-age adults (15-59 years old) and other age groups (0-14 years old: p-value=0.16; 60 years and over: p-value=0.33), whilst susceptibility to SARS-CoV-2 infection was estimated to increase with age (p-value=0.03). In addition, transmission risk was higher for household contacts (p-value<0.001), decreased for higher generations within a cluster (second generation: odds ratio=0.13, p-value<0.001; generations 3-4: odds ratio=0.05, p-value<0.001, relative to generation 1), and decreased for infectors with a larger number of contacts (p-value=0.04). InterpretationOur findings warn of the possible relevant contribution of children to SARS-CoV-2 transmission. When lockdown interventions are in place, we found that odds of transmission are highest in the household setting but, with the relaxation of interventions, other settings (including schools) could bear a higher risk of transmission. Moreover, the estimated relevant fraction of pre-symptomatic and asymptomatic transmission highlight the importance of large-scale testing, contact tracing activities, and the use of personnel protective equipment during the COVID-19 pandemic.
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Objective@#To understand the epidemiologic characteristics and pathogen spectrum of hand, foot and mouth disease (HFMD) in Hunan Province during 2008—2017 and provide the basis for the prevention and control strategy of hand, foot and mouth disease.@*Methods@#Collecting data from national disease reporting information system throughout 2008—2017, the descriptive epidemiological method were used to analyze the data of HFMD monitoring and the result of pathogenic agent detection.@*Results@#A total of 1, 255, 530 HFMD cases were reported throughout 2008—2017, including 10097 severe cases and 394 deaths. The average annual attack rate is 190.38/100, 000. The peak incidence of HFMD occurred in summer and fall. The reported incidence is on the rise. The number of critically ill and the number of deaths is declining. Proportion of male cases was higher than that of females. The majority of the children were those under 5 years of age. Enterovirus (EV)-A71, coxsackievirus (CV)-A16 and other other EV positive cases accounted for 33.29%, 20.04% and 46.67% of laboratory diagnosed cases.@*Conclusions@#The epidemic of hand, foot and mouth disease in Hunan has obvious seasonal and population characteristics. There are different dominant pathogens causing HFMD in different years.
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Objective To estimate the serotype and age-specific hospitalization burden associated with hand,foot and mouth disease (HFMD) in Anhua county of Hunan province,between October 2013 and September 2016.Methods We collected hospitalization records of HFMD patients from 6 virological surveillance hospitals,and reimbursement records through new rural cooperative medical system from 23 township health centers to estimate the age-specific hospitalization burden of HFMD in Anhua.Combined with the results of virological surveillance,the serotype-specific hospitalization burden of HFMD in Anhua,was estimated.Results During the three years,it was estimated that 3 541 clinical diagnosed HFMD cases,including 3 146 laboratory-confirmed HFMD cases,were hospitalized in Anhua,but only one was diaguosed as being severe.The estimated average hospitalization rate was 723/100 000(95％C1:699/100 000-747/100 000) for clinical diagnosed HFMD and 642/100 000 (95％ CI:620/100 000-665/100 000) for laboratory-confirmed HFMD between October 2013 and September 2016.The cases caused by Cox A16 (208/100 000) and Cox A6 (202/100 000) had higher hospitalization rates compared with the cases caused by EV71 (130/100 000),Cox A10 (38/100 000) and other enterovirus (64/100 000),and the difference was statistically significant (P＜0.001).HFMD-associated hospitalization rates peaked in children aged 1 year (3 845/100 000),and then decreased with age.Compared with the hospitalized HFMD caused by EV71 and Cox A16,Cox A6-associated hospitalizations mainly occurred in younger age groups (P＜0.001).Conclusion Our study revealed a substantial hospitalization burden associated with mild HFMD caused by EV71,Cox A16,Cox A6 and Cox A10,especially in young children,in Anhua.
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Objective To estimate the serotype and age-specific hospitalization burden associated with hand,foot and mouth disease (HFMD) in Anhua county of Hunan province,between October 2013 and September 2016.Methods We collected hospitalization records of HFMD patients from 6 virological surveillance hospitals,and reimbursement records through new rural cooperative medical system from 23 township health centers to estimate the age-specific hospitalization burden of HFMD in Anhua.Combined with the results of virological surveillance,the serotype-specific hospitalization burden of HFMD in Anhua,was estimated.Results During the three years,it was estimated that 3 541 clinical diagnosed HFMD cases,including 3 146 laboratory-confirmed HFMD cases,were hospitalized in Anhua,but only one was diaguosed as being severe.The estimated average hospitalization rate was 723/100 000(95％C1:699/100 000-747/100 000) for clinical diagnosed HFMD and 642/100 000 (95％ CI:620/100 000-665/100 000) for laboratory-confirmed HFMD between October 2013 and September 2016.The cases caused by Cox A16 (208/100 000) and Cox A6 (202/100 000) had higher hospitalization rates compared with the cases caused by EV71 (130/100 000),Cox A10 (38/100 000) and other enterovirus (64/100 000),and the difference was statistically significant (P＜0.001).HFMD-associated hospitalization rates peaked in children aged 1 year (3 845/100 000),and then decreased with age.Compared with the hospitalized HFMD caused by EV71 and Cox A16,Cox A6-associated hospitalizations mainly occurred in younger age groups (P＜0.001).Conclusion Our study revealed a substantial hospitalization burden associated with mild HFMD caused by EV71,Cox A16,Cox A6 and Cox A10,especially in young children,in Anhua.
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OBJECTIVE@#To investigate the epidemiological situation and temporal-spatial clustering changes of hand-foot-mouth disease (HFMD) in Hunan. @*METHODS@#Spatial autocorrelation and temporal-spatial clustering analysis were used to analyze the HFMD in Hunan. @*RESULTS@#The incidence rates of HFMD ranged from 54.31/10 million to 318.06/10 million between 2009 and 2015 in Hunan. Cases mainly displayed in 5-year-old or even younger children and there were two epidemic periods each year. HFMD cases did not show a random distribution but with significant spatial aggregation. When local autocorrelation analysis was applied at the county/district level, 4 hot spots in Changsha, Yiyang, Loudi and Zhuzhou were discovered. The tendency for temporal and spatial clustering existed among HFMD cases in Hunan. The temporal dimension of HFMD was from April to July annually. Clustering areas gathered in the northern regions in 2009 and in the middle regions from 2010 to 2012. They moved to middle-southern regions in 2013 or 2014 and middle-western regions in 2015. @*CONCLUSION@#The HFMD incidence from 2009 to 2015 in Hunan showed temporal and spatial clustering tendency, with the shifting trend of clustered areas toward south and west.
