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We aimed to understand the temporal dynamics of SARS‐CoV‐2 reinfection risk and assess the impact of inactivated vaccination on the occurrence of reinfection. We investigated the reinfection risk of SARS‐CoV‐2 from November 1, 2022, to February 12, 2023, when China rapidly lifted the zero‐COVID policy. The study subjects were those who were first infected during the zero‐COVID period between January 1, 2020, and October 31, 2022, in Dalian city, China. Among the 1961 previous infections, 126 (6.4%, 95% CI: 5.4, 7.5) were reinfected. The risk of reinfection increased over time since initial infection. Compared with those who did not receive or received one dose of inactivated vaccine, receiving two or three doses was associated with additional protection against reinfection among individuals who were infected with pre‐Omicron more than a year earlier, with the OR ranged from 0.33 (95% CI: 0.03, 1.83) to 0.91 (95% CI: 0.22, 3.27). In contrast, no protective effect from two or three doses of vaccines against reinfection was observed among those who were first infected with Omicron variants within a year. Primary or booster vaccination contributed to limited protection against reinfection or symptomatic reinfection among individuals infected with Omicron SARS‐CoV‐2 within a year. However, a booster dose after 1 year of natural infection may provide additional protection against reinfection. [ABSTRACT FROM AUTHOR]

• A shorter incubation period and latent period were identified for the Omicron variant. • The transmission risk peaked at the day of symptom onset. • The proportion of presymptomatic transmission was 33.6% for the Omicron variant. • Measures like lockdowns were proven effective in controlling the Omicron outbreak. We aimed to explore the transmission dynamics of the Omicron BA.1.1 variant in an outbreak in China. We constructed 113 transmission pairs based on the time of exposure and symptom onset for identified infectors and infectees, using the epidemiological data collected during an outbreak in Hangzhou, Zhejiang province, China, between January and February 2022. The key epidemiological parameters were estimated. The mean estimates of the incubation period and latent period distributions were 3.8 days (95% credible interval: 3.5, 4.1) and 3.1 days (2.8, 3.5), respectively. The overall transmission risk peaked at symptom onset, and we estimated that 33.6% (24.8, 42.5) of transmission occurred before symptom onset. The forward generation time decreased from 5.2 days (4.7, 5.7) at the start of the outbreak to 2.2 days (2.0, 2.5) by the end. Allowing this variation over time in the generation time distribution, we estimated that the reproduction number dropped rapidly from 9.5 (3.5, 18.4) to 0.8 (0.3, 1.5) over the outbreak. Shorter incubation period and latent period were estimated for the Omicron BA.1.1 variant. Stringent public health measures prevented a large epidemic by reducing transmission, as indicated by the shortened generation time. [ABSTRACT FROM AUTHOR]

Using detailed exposure information on COVID-19 cases, we estimated the mean latent period to be 5.5 (95% CI: 5.1–5.9) days, shorter than the mean incubation period (6.9 days). Laboratory testing may allow shorter quarantines since 95% of COVID-19 cases shed virus within 10.6 (95% CI: 9.6–11.6) days of infection. [ABSTRACT FROM AUTHOR]

Background: To understand Clonorchis sinensis reinfection and the determinants of reinfection in endemic areas is important in establishment of control measures.Methods: A prospective cohort study was implemented in Hengxian County, Guangxi, China. Individuals with C. sinensis infection were completely treated, and those cured were enrolled as study subjects and followed up for 3, 6, and 12 months. The reinfection frequency and incidence were calculated, and a multivariable Cox proportional hazard model was constructed to capture reinfection determinants.Results: Among 635 enrolled subjects, 436 (68.7%) completed follow-up. Of these, 177 (40.6%) were reinfected; 133 (75.1%) were reinfected once, 41 (23.2%) twice, and 3 (1.7%) three times. The incidence of reinfection was 64.0 per 100 person-years. Men (adjusted hazard ratio [aHR], 1.67; 95% confidence interval [CI], 1.14-2.44), those with underlying diseases (aHR, 1.41; 95% CI, 1.02-1.95), and those with moderate- or heavy-intensity infections (aHR, 1.45; 95% CI, 1.14-1.85) had increasing reinfection probabilities.Conclusions: C. sinensis reinfection is high in endemic areas. Men and high-intensity infection are important determinants of reinfection. Repeated chemotherapy is necessary to control reinfection and its associated morbidities, especially in high-risk individuals. In addition, behavioral education is advised to decrease overall reinfection in endemic areas. [ABSTRACT FROM AUTHOR]

Incubation period is an important parameter to inform quarantine period and to study transmission dynamics of infectious diseases. We conducted a systematic review and meta-analysis on published estimates of the incubation period distribution of coronavirus disease 2019, and showed that the pooled median of the point estimates of the mean, median and 95th percentile for incubation period are 6.3 days (range, 1.8–11.9 days), 5.4 days (range, 2.0–17.9 days), and 13.1 days (range, 3.2–17.8 days), respectively. Estimates of the mean and 95th percentile of the incubation period distribution were considerably shorter before the epidemic peak in China compared to after the peak, and variation was also noticed for different choices of methodological approach in estimation. Our findings implied that corrections may be needed before directly applying estimates of incubation period into control of or further studies on emerging infectious diseases. [ABSTRACT FROM AUTHOR]

Tracing and isolation of close contacts is used to control outbreaks of coronavirus disease 2019 (COVID‐19) in China. However, risk factors associated with the occurrence of COVID‐19 among close contacts have not been well described. A total of 106 household contacts were included in this study, of whom 19 developed into COVID‐19 cases, and the secondary attack rate was 17.9%. Multivariable analysis showed that increasing risk of occurrence of COVID‐19 among household contacts was associated with female index patients (adjusted hazard ratio [aHR] = 3.84, 95% CI = 1.07–13.78), critical disease index patients (aHR = 7.58, 95% CI = 1.66–34.66), effective contact duration with index patients > 2 days (aHR = 4.21, 95% CI = 1.29–13.73), and effective contact duration > 11 days (aHR = 17.88, 95% CI = 3.26–98.01). The sex and disease severity of index patients with COVID‐19 and longer effective contact duration with patients with confirmed COVID‐19 could help epidemiologists to identify potential COVID‐19 cases among household contacts at an early stage. [ABSTRACT FROM AUTHOR]

Background: The emergence and re-emergence of scrub typhus has been reported in the past decade in many global regions. In this study, we aim to identify potential scrub typhus infection risk zones with high spatial resolution in Qingdao city, in which scrub typhus is endemic, to guide local prevention and control strategies. Methodology/Principal findings: Scrub typhus cases in Qingdao city during 2006–2018 were retrieved from the Chinese National Infectious Diseases Reporting System. We divided Qingdao city into 1,101 gridded squares and classified them into two categories: areas with and without recorded scrub typhus cases. A boosted regression tree model was used to explore environmental and socioeconomic covariates associated with scrub typhus occurrence and predict the risk of scrub typhus infection across the whole area of Qingdao city. A total of 989 scrub typhus cases were reported in Qingdao from 2006–2018, with most cases located in rural and suburban areas. The predicted risk map generated by the boosted regression tree models indicated that the highest infection risk areas were mainly concentrated in the mid-east and northeast regions of Qingdao, with gross domestic product (20.9%±1.8% standard error) and annual cumulative precipitation (20.3%±1.1%) contributing the most to the variation in the models. By using a threshold environmental suitability value of 0.26, we identified 757 squares (68.7% of the total) with a favourable environment for scrub typhus infection; 66.2% (501/757) of the squares had not yet recorded cases. It is estimated that 6.32 million people (72.5% of the total population) reside in areas with a high risk of scrub typhus infection. Conclusions/Significance: Many locations in Qingdao city with no recorded scrub typhus cases were identified as being at risk for scrub typhus occurrence. In these at-risk areas, awareness and capacity for case diagnosis and treatment should be enhanced in the local medical service institutes. Author summary: Scrub typhus is a bacterial zoonosis caused by Orientia tsutsugamushi, which is mostly carried by rodents and chigger mites, and occasionally transmitted to humans by bites of infected larval mites. Scrub typhus is geographically endemic across broad areas of south and southeastern Asia, the Pacific islands and northern Australia. In recent years, an obvious increasing trend of the incidence of this disease has been noticed all around the world. China is one of the most endemic country for this disease, with an approximate 10-fold increase of the annual case number from 2006 to 2013. In this study, by using a prediction model for infectious diseases, we found that the highest infection risk area was located at the mid-east and northeast regions of Qingdao, with gross domestic product and precipitation might developed the greatest impact for the occurrence of scrub typhus. Furthermore, 68.7% of the region in Qingdao might have a suitable environment for the occurrence of scrub typhus, with most of them hadn't reported cases yet. This study highlights the emergency to enhance the awareness of this disease and improve the capacity of diagnosis and treatment among medical institutions in high risk areas in Qingdao. [ABSTRACT FROM AUTHOR]

High-intensity clonorchiasis infection is associated with serious outcomes, including cancer. Understanding the infection intensity of Clonorchis sinensis and its risk factors in local endemic regions could facilitate effective control measures. In a county located in a highly endemic area in Guangxi Province, P. R. China, local residents were randomly enrolled in the study; helminth egg examinations were performed with the Kato-Katz method, and the intensity of infection was identified as mild, moderate or heavy. Knowledge, attitudes, and high-risk behaviours were investigated among those infected with Clonorchis sinensis. A total of 2521 local residents participated in this study, and the Clonorchis sinensis-positive proportion was 28.9% (728 persons). Among the infected persons, the percentages of mild, moderate and heavy infections were 66.2%, 28.4% and 5.4%, respectively. Males experienced a higher proportion of moderate and heavy infections (37.5%) than females (18.1%) (p<0.05). The highest infection proportion among the different levels of infection intensity was identified among persons aged 30–59 years (15.7% for moderate and heavy infections). Among the 509 persons who reported eating raw fish, 302 persons (59.3%) had eaten raw fresh fish for more than 10 years, and 131 (25.7%) persons ate raw fish ≥12 times a year. Multivariate logistic regression revealed that eating raw fish 12–50 times in the last year (adjusted odds ratio [aOR] = 1.74, 95%CI: 1.09–2.80) and eating raw fish >50 times in the last year (aOR = 2.89, 95%CI: 1.20–7.50) were risk factors for high-intensity infections (moderate and heavy). The overall infection proportion was high in the study area, with a large group of residents experiencing high-intensity infections. High frequency of raw fish consumption was associated with high-intensity infections. Intervention strategies targeting people with a high frequency of raw fish consumption should be implemented to reduce the probability of severe consequences. Author summary: Clonorchiasis, which is caused by Clonorchis sinensis, is one of the most endemic parasite diseases in China. Humans get infected by eating the raw or undercooked freshwater fish that contain the nymphal stage of Clonorchis sinensis. There are about 15 million cases globally with 85% of those in China. Two major endemic areas were found in China, including Guangdong and Guangxi Province in the south part of China, and Heilongjiang, Jilin and Liaoning Province in the north part of China. In this study, by analysing the dataset from one county in Guangxi Province, we found the overall proportion of infection was high, with one third of infection persons were classified as high intensity of infection. Male and persons aged 30–59 years developed higher burden of infection. Besides, persons who eat high frequency of raw fish developed high intensity of infection. Health education on the high risk populations should be strengthened to change the diet custom. Other measure such as examination of freshwater fish in the market should also be implemented. [ABSTRACT FROM AUTHOR]

Scrub typhus is a life‐threatening vector‐borne disease. During the past decade, the number of areas affected by this disease has expanded in many countries. In this study, we aim to identify the spatiotemporal and demographic characteristics of scrub typhus in Southwest China, an emerging endemic region for scrub typhus. Population‐based surveillance data capturing scrub typhus cases in two provinces of Southwest China during 2006–2017 were retrieved. Descriptive temporal and spatial analyses were conducted and stratified by age group. The space‐time scan statistic was used to identify spatiotemporal clusters of scrub typhus occurrence at the county level. During the study period, 30,001 scrub typhus cases were recorded in Southwest China, with a total of 61.0% (191/313) of counties being affected; most cases (94.3%) occurred in rural areas. The annual incidence rate increased substantially from 0.25/100,000 in 2006 to 5.38/100,000 in 2017 (>21‐fold change). The 0‐ to 4‐year‐old and 45‐ to 64‐year‐old subgroups had the highest cumulative incidence rates (57.46 and 32.98/100,000, respectively). Furthermore, since 2006, the 0‐ to 4‐year‐old (slope = 0.83, p <.01) and 45–64‐year‐old (slope = 0.69, p <.01) age groups have had the highest increases in incidence of all age groups. The most likely spatial cluster of overall cases (relative risk = 4.13, p <.01) occurred in the southern region of Southwest China and included 41 high‐risk counties. In conclusion, scrub typhus appears to be widely distributed and rapidly increasing in Southwest China. Young children and middle‐aged adults were the most severely affected groups, and the disease appeared to predominantly cluster in the southern part of Southwest China. Further in‐depth surveys to determine the epidemiological characteristics and driving factors of this emerging disease and to facilitate effective control programmes among high‐risk groups in the affected areas should be promoted. [ABSTRACT FROM AUTHOR]

• Introducing a novel action recognition model that enhances GCNs using skeleton data. • Addressing issues like oversmoothing, high computational cost, and inflexibility. • Outperforming 2s-AGCN in NTU RGB+D, NTU RGB+D 120 and Kinetics-Skeleton datasets. Action recognition has shown a broad prospect for application in human–computer interaction and autonomous vehicles. According to skeleton data being lightweight and robust to environmental disturbance, skeleton-based methods are increasingly used in action recognition. Existing Graph Convolutional Networks (GCNs) have limitations such as Global Average Pooling (GAP) causing information oversmoothing, attention mechanism increasing computational complexity, and fixed spatial configuration partition strategy limiting flexibility. Our model overcomes these limitations by incorporating Temporal Covariance Pooling (TCP) for better feature utilization, Sample-Shared attention for weight sharing, and a Comprehensive Receptive Field strategy for optimal joint connections. Experiments show that the recognition accuracy of our model outperforms baseline 2s-AGCN by 1.1 % and 0.7 % under X-Sub and X-View for NTU RGB + D dataset, 1.8 % and 1.9 % in X-Sub and X-Set for NTU RGB + D 120 dataset, and 1.6 % on Kinetics-Skeleton dataset. [ABSTRACT FROM AUTHOR]

• Eating undercooked pig liver can lead to hepatitis E virus infection. • Identical sequences of hepatitis E virus indicates common-source infection. • Symptomatic hepatitis E cases have elevated liver alanine aminotransferase levels. In July 2018, recurrent hepatitis E cases were reported from a factory in Qingdao City, China. The aim of this study was to identify additional cases, and help prevent future incidents by identifying possible risk factors for infection. Participants were asked to provide blood samples for hepatitis E virus (HEV) IgM and IgG antibodies screening, as well as liver function test. A questionnaire that assessed demographics, potential risk factors, and clinical symptoms was completed by participants. HEV RNA genotyping was performed using a nested Reverse Transcriptional Polymerase Chain Reaction (RT-PCR) method. Adjusted Poisson regression model for participant characteristics and risk factors was constructed for multivariate analysis. Overall, 41(14.5%, 41/283) participants had recent acute infection (21 of these were symptomatic). The result of multivariate analysis demonstrated a significant association of acute HEV infection with consumption of pig liver within the past two months (Relative Risk 2.61, 95% confidence interval (CI) 1.10–6.17, p = 0.0294). Sequencing of HEV RNA from seventeen acute cases indicated three HEV isolates of genotype 4 induced this outbreak. This was probably a common-source foodborne hepatitis E outbreak, related to the consumption of undercooked pig liver. [ABSTRACT FROM AUTHOR]

Social distancing measures (SDMs) are community-level interventions that aim to reduce person-to-person contacts in the community. SDMs were a major part of the responses first to contain, then to mitigate, the spread of SARS-CoV-2 in the community. Common SDMs included limiting the size of gatherings, closing schools and/or workplaces, implementing work-from-home arrangements, or more stringent restrictions such as lockdowns. This systematic review summarized the evidence for the effectiveness of nine SDMs. Almost all of the studies included were observational in nature, which meant that there were intrinsic risks of bias that could have been avoided were conditions randomly assigned to study participants. There were no instances where only one form of SDM had been in place in a particular setting during the study period, making it challenging to estimate the separate effect of each intervention. The more stringent SDMs such as stay-at-home orders, restrictions on mass gatherings and closures were estimated to be most effective at reducing SARS-CoV-2 transmission. Most studies included in this review suggested that combinations of SDMs successfully slowed or even stopped SARS-CoV-2 transmission in the community. However, individual effects and optimal combinations of interventions, as well as the optimal timing for particular measures, require further investigation. This article is part of the theme issue 'The effectiveness of non-pharmaceutical interventions on the COVID-19 pandemic: the evidence'. [ABSTRACT FROM AUTHOR]

Scrub typhus, a miteborne rickettsiosis, has emerged in many areas globally. We analyzed the incidence and spatial-temporal distribution of scrub typhus in China during 1952-1989 and 2006-2016 using national disease surveillance data. A total of 133,623 cases and 174 deaths were recorded. The average annual incidence was 0.13 cases/100,000 population during 1952-1989; incidence increased sharply from 0.09/100,000 population in 2006 to 1.60/100,000 population in 2016. The disease, historically endemic to southern China, has expanded to all the provinces across both rural and urban areas. We identified 3 distinct seasonal patterns nationwide; infections peaked in summer in the southwest, summer-autumn in the southeast, and autumn in the middle-east. Persons >40 years of age and in nonfarming occupations had a higher risk for death. The changing epidemiology of scrub typhus in China warrants an enhanced disease control and prevention program. [ABSTRACT FROM AUTHOR]

Background: The Qingdao diabetes risk score (QDRS) is an accurate tool for identifying individuals who are at a high risk for diabetes. This study was designed to determine the association of the QDRS with the incidence of diabetes in the general population in urban and rural settings. Methods: A stratified, random, cluster-sampling method was used to select representative individuals in 2006 and 2009, and the follow-up survey was conducted from 2012 to 2015. Of 5851 participants, 3248 were available in cohort study. The individuals without data of FPG, 2 h PG was excluded in follow-up survey. Finally, a total of 3033 participants were included. Waist circumference, age, and family history of diabetes were collected to determine the QDRS. Cox proportional hazards regression models were used to evaluate the association of QDRS and BMI with the incidence of diabetes. Further, we assessed the relative excess risk due to interaction (RERI), synergy index (S), and attributable proportion due to interaction (AP). Results: Their age-standardized cumulative incidence of diabetes was 16.9% and 10.8% among the urban and rural populations, respectively. In both urban and rural settings, individuals with a QDRS ≥ 14 had a significantly higher risk for diabetes than the individuals with a QDRS < 14 (hazard ratio (HR): 2.37 vs. 1.49; 95% CI 1.35–4.15 vs. 1.09–2.04). Further, having a QDRS of ≥ 14 concurrently with being overweight/obese showed an additive effect on the risk for diabetes in urban settings (RERI = 1.59, S = 2.34, AP = 42.06%). In contrast, a negative interaction was noted in rural settings (RERI = 0.07, S = 0.89, AP = 4.55%). Conclusions: Having a QDRS ≥ 14 demonstrated a strong positive association with the incidence of diabetes. An elevated QDRS combined with BMI showed value in predicting the incidence of diabetes among high-risk populations for diabetes in urban but not rural settings. [ABSTRACT FROM AUTHOR]

Background: To investigative the association of triglycerides (TG) and total cholesterol (TC) concentrations with impaired fasting glucose/ impaired glucose tolerance (IFG/IGT) in Chinese adults.Methods: The population-based cross-sectional diabetes survey was conducted in 2006 and 2009 in Qingdao, separately. 4400 participants (1 793 men and 2607 women) were include in current analysis. IFG/IGT was defined according to fasting plasma glucose (FPG) and/or 2 h post-load plasma glucose (2 h PG). Logistic regression models and areas under receiver operating characteristic curves (AUROC) were performed to estimate the associations between TG, TC levels and IFG/IGT.Results: Spearman analysis showed that serum TG and TC was independently and positively associated with FPG and 2 h PG. As compared with normoglycaemia, the odds ratio[(95% confidence intervals), OR(95%CI)] for IFG/IGT corresponding to hypertriglyceridemia (HTG) were 1.61 (1. 17, 2. 22) in men and 1.57(1.15, 2.14) in women for TG and accompany with Hypercholesterolemia (HTC) 1.56 (1.15, 2.13) and 1. 20 (0.93, 1.54) for TC, when adjusting for confounding factor. The AUROCs of TG, TC for IFG/IGT were relatively smaller (0.50 < AUROC< 0. 7) in both gender. The optimal cut-offs for TG and TC was 1.61, 4.91 in men and 1. 24, 5. 32 in women, respectively.Conclusions: Evaluated TG in both gender and TC in men were independently associated with the present of the IFG/IGT, yet, could not be an authentic predictors of IFG/IGT in both men and women in current Chinese population. [ABSTRACT FROM AUTHOR]