Wastewater Surveillance Provides Spatiotemporal SARS-CoV-2 Infection Dynamics

Wastewater surveillance(WWS)can leverage its wide coverage,population-based sampling,and high monitoring frequency to capture citywide pandemic trends independent of clinical surveillance.Here we conducted a nine months daily WWS for severe acute respiratory syndrome coronavirus 2(SARSCoV-2)from 12 wastewater treatment plants(WWTPs),covering approximately 80%of the population,to monitor infection dynamics in Hong Kong,China.We found that the SARS-CoV-2 virus concentration in wastewater was correlated with the daily number of reported cases and reached two pandemic peaks three days earlier during the study period.In addition,two different methods were established to estimate the prevalence/incidence rates from wastewater measurements.The estimated results from wastewater were consistent with findings from two independent citywide clinical surveillance programmes(rapid antigen test(RAT)surveillance and serology surveillance),but higher than the cases number reported by the Centre for Health Protection(CHP)of Hong Kong,China.Moreover,the effective reproductive number(R_(t))was estimated from wastewater measurements to reflect both citywide and regional transmission dynamics.Our findings demonstrate that large-scale intensive WWS from WWTPs provides cost-effective and timely public health information,especially when the clinical surveillance is inadequate and costly.This approach also provides insights into pandemic dynamics at higher spatiotemporal resolutions,facilitating the formulation of effective control policies and targeted resource allocation.

Survivability of freeze-dried probiotic Pediococcus pentosaceus strains GS4,GS17 and Lactobacillus gasseri(ATCC 19992)during storage with commonly used pharmaceutical excipients within a period of 120 days

Objective: To examine the survivability and stability of probiotic strains in presence and absence of pharmaceutical excipients for a long period of time at(4 ± 1)℃.Methods: The survival rates of probiotic strains, Pediococcus pentosaceus GS4(MTCC12683)(NCBI HM044322), GS17(NCBI KJ608061) and Lactobacillus gasseri(ATCC 19992), were evaluated. Probiotic strains were lyophilized individually and in combination of excipients(sorbitol, ascorbic acid, fructose and skim milk). The preparation was monitored for 120 d storing at(4 ± 1)℃. During storage, all the preparations were evaluated for viability and stability of probiotic properties like lactic acid production, antimicrobial effect, water activity, and adherence to epithelial cells.Results: Sorbitol, ascorbic acid and skim milk favoured the viability of freeze-dried cells and sustained probiotic properties during storage. Without excipients(control group),strains showed percentage of survivability not more than 70% while strains with excipients survived for 73%–93% for a long period of time.Conclusions: Commonly used excipients can be considered as a vehicle for delivering active principle in probiotic formulation and for sustaining the viability and stability of probiotic strains for a period of 120 d.

Photoperiodic diapause in a subtropical population of Aedes albopictus in Guangzhou,China:optimized fieldlaboratory-based study and statistical models for comprehensive characterization

Background:Aedes albopictus is among the 100 most invasive species worldwide and poses a major risk to public health.Photoperiodic diapause provides a crucial ecological basis for the adaptation of this species to adverse environments.Ae.albopictus is the vital vector transmitting dengue virus in Guangzhou,but its diapause activities herein remain obscure.Methods:In the laboratory,yeast powder and food slurry were compared for a proper diapause determination method,and the critical photoperiod(CPP)was tested at illumination times of 11,11.5,12,12.5,13,and 13.5 h.A 4-parameter logistic(4PL)regression model was selected to estimate the CPP.In the field,the seasonal dynamics of the Ae.albopictus population,egg diapause,and hatching of overwintering eggs were investigated monthly,weekly,and daily,respectively.A distributed lag non-linear model(DLNM)was used to assess the associations of diapause with meteorological factors.Results:In the laboratory,both the wild population and the Foshan strain of Ae.albopictus were induced to diapause at an incidence greater than 80%,and no significant difference(P>0.1)was observed between the two methods for identifying diapause.The CPP of this population was estimated to be 12.312 h of light.In the field,all of the indexes of the wild population were at the lowest levels from December to February,and the Route Index was the first to increase in March.Diapause incidence displayed pronounced seasonal dynamics.It was estimated that the day lengths of 12.111 h at week2016,43 and 12.373 h at week2017,41 contributed to diapause in 50%of the eggs.Day length was estimated to be the main meteorological factor related to diapause.Conclusions:Photoperiodic diapause of Ae.albopictus in Guangzhou of China was confirmed and comprehensively elucidated in both the laboratory and the field.Diapause eggs are the main form for overwintering and begin to hatch in large quantities in March in Guangzhou.Furthermore,this study also established an optimized investigation system and statistical models for the study of Ae.albopictus diapause.These findings will contribute to the prevention and control of Ae.albopictus and mosquito-borne diseases.

The economic burden of influenza-associated outpatient visits and hospitalizations in China: a retrospective survey

Background:The seasonal influenza vaccine coverage rate in China is only 1.9%.There is no information available on the economic burden of influenza-associated outpatient visits and hospitalizations at the national level,even though this kind of information is important for informing national-level immunization policy decision-making.Methods:A retrospective telephone survey was conducted in 2013/14 to estimate the direct and indirect costs of seasonal influenza-associated outpatient visits and hospitalizations from a societal perspective.Study participants were laboratory-confirmed cases registered in the National Influenza-like Illness Surveillance Network and Severe Acute Respiratory Infections Sentinel Surveillance Network in China in 2013.Patient-reported costs from the survey were validated by a review of hospital accounts for a small sample of the inpatients.Results:The study enrolled 529 outpatients(median age:eight years;interquartile range[IQR]:five to 20 years)and 254 inpatients(median age:four years;IQR:two to seven years).Among the outpatients,22.1%(117/529)had underlying diseases and among the inpatients,52.8%(134/254)had underlying diseases.The average total costs related to influenza-associated outpatient visits and inpatient visits were US$155(standard deviation,SD US$122)and US$1,511(SD US$1,465),respectively.Direct medical costs accounted for 45 and 69%of the total costs related to influenza-associated outpatient and inpatient visits,respectively.For influenza outpatients,the mean cost per episode in children aged below five years(US$196)was higher than that in other age groups(US$129–153).For influenza inpatients,the mean cost per episode in adults aged over 60 years(US$2,735)was much higher than that in those aged below 60 years(US$1,417–1,621).Patients with underlying medical conditions had higher costs per episode than patients without underlying medical conditions(outpatients:US$186 vs.US$146;inpatients:US$1,800 vs.US$1,189).In the baseline analysis,inpatients reported costs were 18%higher than those found in the accounts review(n=38).Conclusion:The economic burden of influenza-associated outpatient and inpatient visits in China is substantial,particularly for young children,the elderly,and patients with underlying medical conditions.More widespread influenza vaccination would likely alleviate the economic burden of patients.The actual impact and cost-effectiveness analysis of the influenza immunization program in China merits further investigation.

Vaccination Uncertainties and COVID-19 Prospects in 2021

As we pass the first anniversary of the World Health Organization’s(WHO)declaration of a Public Health Emergency of International Concern(1),we look back at the impact of coronavirus disease 2019(COVID-19)in 2020 and the prospects for the pandemic in 2021.

Travel-related Importation and Exportation Risks of SARS-CoV-2 Omicron Variant in 367 Prefectures(Cities)-China,2022

Introduction:Minimizing the importation and exportation risks of coronavirus disease 2019(COVID-19)is a primary concern for sustaining the“Dynamic COVID-zero”strategy in China.Risk estimation is essential for cities to conduct before relaxing border control measures.Methods:Informed by the daily number of passengers traveling between 367 prefectures(cities)in China,this study used a stochastic metapopulation model parameterized with COVID-19 epidemic characteristics to estimate the importation and exportation risks.Results:Under the transmission scenario(R0=5.49),this study estimated the cumulative case incidence of Changchun City,Jilin Province as 3,233(95%confidence interval:1,480,4,986)before a lockdown on March 14,2022,which is close to the 3,168 cases reported in real life by March 16,2022.In a total of 367 prefectures(cities),127(35%)had high exportation risks according to the simulation and could transmit the disease to 50%of all other regions within a period from 17 to 94 days.The average time until a new infection arrives in a location in 1 of the 367 prefectures(cities)ranged from 26 to 101 days.Conclusions:Estimating COVID-19 importation and exportation risks is necessary for preparedness,prevention,and control measures of COVID-19—especially when new variants emerge.

Social Determinants,Data Science,and Decision Making:The 3-D Approach to Achieving Health Equity in Asia

Improving population health by creating more equitable health systems is a major focus of health policy and planning today.However,before we can achieve equity in health,we must first begin by leveraging all we have learned,and are continuing to discover,about the many social,structural,and environmental determinants of health.We must fully consider the conditions in which people are born,grow,learn,work,play,and age.The study of social determinants of health has made tremendous strides in recent decades.At the same time,we have seen huge advances in how health data are collected,analyzed,and used to inform action in the health sector.It is time to merge these two fields,to harness the best from both and to improve decision-making to accelerate evidence-based action toward greater health equity.

Characterizing Human Collective Behaviors During COVID-19 — Hong Kong SAR, China, 2020

Summary What is already known about this topic?People are likely to engage in collective behaviors online during extreme events,such as the coronavirus disease 2019(COVID-19)crisis,to express awareness,take action,and work through concerns.

我国HIV感染者CD_4^+T淋巴细胞检测能力的研究

目前，人类关于HIV感染的检测项目很多，其中CD4^＋ T淋巴细胞的检测已成为评估HIV感染者疾病状况切实可行和相对经济的检测项目，CD4^＋ T淋巴细胞水平用来监测不同临床阶段HIV感染者免疫状况的变化，判定HIV感染者病程，预测机会性感染的出现以及评价抗HIV药物疗效。从2006年起准确检测CD4^＋ T淋巴细胞计数已经成为判断是否开始治疗AIDS和HIV感染者以及治疗效果观察对比的关键。国际上如美国CDC、英国国家室间质量评价系统（The United Kingdom National External Quality Assessment Service，NEQAS）、加拿大HIV／AIDS质量评价和免疫标准化体系（Quality Assessment and Standardization for Immunological Measures Relevant to HIV／AIDS，QASI）定期发放质控品，

Epidemic Surveillance of Influenza Infections:A Network-Free Strategy—Hong Kong Special Administrative Region,China,2008–2011

Introduction:The ease of coronavirus disease 2019(COVID-19)non-pharmacological interventions and the increased susceptibility during the past COVID-19 pandemic could be a precursor for the resurgence of influenza,potentially leading to a severe outbreak in the winter of 2022 and future seasons.The recent increased availability of data on Electronic Health Records(EHR)in public health systems,offers new opportunities to monitor individuals to mitigate outbreaks.Methods:We introduced a new methodology to rank individuals for surveillance in temporal networks,which was more practical than the static networks.By targeting previously infected nodes,this method used readily available EHR data instead of the contactnetwork structure.Results:We validated this method qualitatively in a real-world cohort study and evaluated our approach quantitatively by comparing it to other surveillance methods on three temporal and empirical networks.We found that,despite not explicitly exploiting the contacts’network structure,it remained the best or close to the best strategy.We related the performance of the method to the public health goals,the reproduction number of the disease,and the underlying temporal-network structure(e.g.,burstiness).Discussion:The proposed strategy of using historical records for sentinel surveillance selection can be taken as a practical and robust alternative without the knowledge of individual contact behaviors for public health policymakers.

Heterogeneous influence of individuals’ behavior on mask efficacy in gathering environments

Wearing masks is an easy way to operate and popular measure for preventing epidemics.Although masks can slow down the spread of viruses,their efficacy in gathering environments involving heterogeneous person-to-person contacts remains unknown.Therefore,we aim to investigate the epidemic prevention effect of masks in different real-life gathering environments.This study uses four real interpersonal contact datasets to construct four empirical networks to represent four gathering environments.The transmission of COVID-19 is simulated using the Monte Carlo simulation method.The heterogeneity of individuals can cause mask efficacy in a specific gathering environment to be different from the baseline efficacy in general society.Furthermore,the heterogeneity of gathering environments causes the epidemic prevention effect of masks to differ.Wearing masks can greatly reduce the probability of clustered epidemics and the infection scale in primary schools,high schools,and hospitals.However,the use of masks alone in primary schools and hospitals cannot control outbreaks.In high schools with social distancing between classes and in workplaces where the interpersonal contact is relatively sparse,masks can meet the need for prevention.Given the heterogeneity of individual behavior,if individuals who are more active in terms of interpersonal contact are prioritized for mask-wearing,the epidemic prevention effect of masks can be improved.Finally,asymptomatic infection has varying effects on the prevention effect of masks in different environments.The effect can be weakened or eliminated by increasing the usage rate of masks in high schools and workplaces.However,the effect on primary schools and hospitals cannot be weakened.This study contributes to the accurate evaluation of mask efficacy in various gathering environments to provide scientific guidance for epidemic prevention.