Despite widespread mumps vaccination, recurrent outbreaks persist globally, underscoring the need to clarify sex- and age-specific transmission mechanisms. This study characterizes mumps epidemiology in Chengdu (2008–2019) and quantifies sex- and age-specific transmission pathways using a mechanistic modeling framework. A sex- and age-structured Susceptible–Exposed–Pre-symptomatic–Symptomatic–Asymptomatic–Recovered (SEPIAR) model incorporating seasonal forcing was developed to estimate time-varying reproduction numbers (Rt) across 64 transmission pathways. A total of 40,087 cases were reported (annual incidence: 21.72 per 100,000), with the highest burden among male students aged 5–14 and seasonal peaks in May–July and November–December. The model achieved good fit across demographic groups (R² = 0.13–0.73, P < 0.001). Females aged 10–14 exhibited the strongest transmission potential, particularly toward males aged 0–14 (median Rt: 1.18 to males 5–9; 0.75 to males 0–4; 0.55 within the same group). Sensitivity and empirical uncertainty analyses confirmed the robustness of these transmission patterns. Sex and age may play an important role in shaping mumps transmission dynamics in Chengdu. The SEPIAR model may offer a useful framework for characterizing transmission pathways and identifying groups that could contribute disproportionately to spread. Interventions such as targeted vaccination during seasonal peaks, considering booster doses for females aged 10–14, enhancing surveillance in high‑incidence districts, and improving reporting capacity in rural areas could help reduce transmission and may support more effective and sustained mumps control in large urban settings.

BACKGROUND:Scarlet fever (SF) is an acute infectious disease that poses a significant public health threat; however, its transmission dynamics, particularly the impact of asymptomatic carriers and socioeconomic determinants, remain unclear. METHODS:We developed a susceptible-exposed-infectious-asymptomatic-recovered (SEIAR) model that incorporates asymptomatic infections to estimate the time-varying reproduction number (Rt) for SF in Chengdu (2005-2019) using local epidemiological data. The model was evaluated using the coefficient of determination (R²), and sensitivity analysis confirmed its robustness. We further integrated Boruta, Extreme Gradient Boosting (XGBoost), and SHapley Additive exPlanations (SHAP) to systematically assess the influence of socioeconomic variables on Rt. RESULTS:Between 2005 and 2019, Chengdu reported 11,499 cases of SF, with an average incidence of 4.87 per 100,000. Two distinct seasonal peaks occurred in April-May and November-December, and incidence rates were notably lower during school holidays. The majority of cases affected children aged 3-7, with a male-to-female ratio of 1.59:1. In addition, core districts such as Wuhou and Xindu exhibited the highest incidence. The SEIAR model demonstrated strong predictive performance (overall R² = 0.831, P < 0.001) and estimated a median Rt of 0.963; however, several regions exceeded this threshold, with Rt peaking approximately two months prior to incidence surges. Spatial analyses revealed significant clustering in central urban areas, and integrated socioeconomic analysis identified the one-child rate as the primary driver of Rt, followed by population density and healthcare facility density (P < 0.01). CONCLUSION:By integrating epidemiological data with socioeconomic factors, this study quantitatively elucidates the transmission characteristics of SF in Chengdu, providing data-driven support for monitoring and targeted intervention strategies in the absence of vaccination.

Objectives This study investigates mumps epidemiology in Chengdu (2008–2019), focusing on sex and age-specific transmission characteristics. Methods A sex- and age-specific Susceptible – Exposed – Pre-symptomatic – Symptomatic Infected – Asymptomatic Infected – Recovered (SEPIAR) model, adjusted for seasonal variations, was employed to categorize the population and analyze transmission dynamics. Results Over the study period, 40,087 mumps cases were reported in Chengdu, with an annual incidence of 21.72 per 100,000, peaking in 2011 at 40.83 per 100,000. Incidence rates were highest among male students aged 5–14, with significant seasonal peaks in May-July and November-December. District-wise, Wenjiang and Jinniu had the highest rates (45.45 and 43.25 per 100,000), while Jianyang city had the lowest (3.26 per 100,000). The SEPIAR model demonstrated robust fitting across demographics (R² = 0.13–0.73, P < 0.001). Notably, females aged 10–14 exhibited the highest transmission risk to males aged 0–14, with all mean time-varying reproduction numbers (Rt) exceeding 1. The median Rt for females aged 10–14 to males aged 5–9 was 1.18, to males aged 0–4 was 0.75, and within the same age group was 0.55. Conclusions This study underscores the critical role of sex and age in mumps transmission and validates the utility of the SEPIAR model for outbreak analysis. To mitigate transmission, we recommend: 1) targeted vaccination campaigns during seasonal peaks, 2) prioritizing booster doses for females aged 10–14, 3) strengthening surveillance in high-incidence districts, and 4) improving healthcare reporting in rural regions. These strategies are vital for achieving sustained mumps control in megacities.

Background:The measles-mumps-rubella (MMR) trivalent vaccine constitutes a cornerstone in controlling mumps incidence. However, variations in vaccination timing coupled with the gradual waning of vaccine-induced immunity have contributed to an increase in mumps cases among adolescents, alongside dynamic shifts in age distribution. This study aims to elucidate the optimal vaccination strategies for both the general population and age-specific cohorts through a comprehensive, multidimensional evaluation. Methods:We systematically collected and integrated global annual average mumps incidence data (2000-2023) from 23 countries and immunization schedule databases to construct 16 hypothetical vaccination strategies, including the baseline regimen (a single dose administered at 18-24 months), an improved timing regimen (an additional primary dose at 8-9 months before 24 months), and booster regimens (one to two supplementary doses during childhood or adolescence). We developed an individual-based disease transmission model (IBM) incorporating real-time vaccination, age growth, and age-specific contact frequency and preference, driven by estimated time-varying reproduction numbers, to simulate the impact of different strategies after five years of steady-state implementation on cumulative case counts, overall infection numbers, outbreak magnitude, and age-specific infection risks. This comprehensive evaluation framework enables us to assess the impact of dosing and vaccination timing on the immunological control of mumps. Findings:For overall population control, a strategy entailing a single vaccine dose at 18-24 months, a booster at 13-14 years, and another at 18-19 years yielded optimal results, achieving a reduction of 99.79% in both cumulative infections and cases over the subsequent five years. When implementing immunization exclusively before 24 months, a dual-dose primary regimen reduced cumulative infections and cases by an additional 4.79% and 4.91% over the subsequent five years, respectively, compared to a single-dose approach. Moreover, within identical booster vaccination age groups, completing a dual-dose primary immunization before 24 months generally provided superior protection relative to the single-dose protocol. Age-specific analyses further revealed that while the dual-dose strategy before 24 months lowered the proportion of cases and infections in the 0-4 year age group compared to the single-dose regimen, the absolute numbers remained largely unchanged; under the same primary immunization framework, delaying the administration of the final dose decreased the infection proportion in the 20-25 year age group, with a dual-dose booster implemented after age 2 effectively minimizing the proportion of cases among individuals over 20. Notably, administering the booster at ages 13-14 years consistently suppressed the primary infection peak observed in individuals aged 10-14 years, reducing infection numbers by more than 99.00%. Interpretation:A phased immunization strategy that integrates primary vaccination with sequential booster doses may help reduce the transmission of mumps in our simulations. Model projections suggest that prioritizing booster vaccinations during adolescence could lower infection risks among vulnerable age groups and may provide additional protection for women of reproductive age. Funding:National Key Research and Development Program of China (2024YFC2311404).

Background:Quantitative assessment of the risk of local transmission from imported dengue cases makes a great challenge to the development of public health in China. The purpose of this study is to observe the risk of mosquito-borne transmission in Xiamen City through ecological and insecticide resistance monitoring. Quantitative evaluation of mosquito insecticide resistance, community population and the number of imported cases affecting the transmission of dengue fever (DF) in Xiamen was carried out based on transmission dynamics model, so as to reveal the correlation between key risk factors and DF transmission.Methods:Based on the dynamics model and combined with the epidemiological characteristics of DF in Xiamen City, a transmission dynamics model was built to simulate the secondary cases caused by imported cases to evaluate the transmission risk of DF, and to explore the influence of mosquito insecticide resistance, community population and imported cases on the epidemic situation of DF in Xiamen City.Results:For the transmission model of DF, when the community population is between 10,000 and 25,000, changing the number of imported DF cases and the mortality rate of mosquitoes will have an impact on the spread of indigenous DF cases, however, changing the birth rate of mosquitoes did not gain more effect on the spread of local DF transmission.Conclusions:Through the quantitative evaluation of the model, this study determined that the mosquito resistance index has an important influence on the local transmission of dengue fever caused by imported cases in Xiamen, and the Brayton index can also affect the local transmission of the disease.

Background In September 2021, there was an outbreak of coronavirus disease 2019 (COVID-19) in Xiamen, China. Various non-pharmacological interventions (NPIs) and pharmacological interventions (PIs) have been implemented to prevent and control the spread of the disease. This study aimed to evaluate the effectiveness of various interventions and to identify priorities for the implementation of prevention and control measures. Methods The data of patients with COVID-19 were collected from 8 to 30 September 2021. A Susceptible-Exposed-Infectious-Recovered (SEIR) dynamics model was developed to fit the data and simulate the effectiveness of interventions (medical treatment, isolation, social distancing, masking, and vaccination) under different scenarios. The effective reproductive number (Reff) was used to assess the transmissibility and transmission risk. Results A total of 236 cases of COVID-19 were reported in Xiamen. The epidemic curve was divided into three phases (Reff = 6.8, 1.5, and 0). Notably, the cumulative number of cases was reduced by 99.67% due to the preventive and control measures implemented by the local government. In the effective containment stage, the number of cases could be reduced to 115 by intensifying the implementation of interventions. The total number of cases (TN) could be reduced by 29.66–95.34% when patients voluntarily visit fever clinics. When only two or three of these measures are implemented, the simulated TN may be greater than the actual number. As four measures were taken simultaneously, the TN may be <100, which is 57.63% less than the actual number. The simultaneous implementation of five interventions could rapidly control the transmission and reduce the number of cases to fewer than 25. Conclusion With the joint efforts of the government and the public, the outbreak was controlled quickly and effectively. Authorities could promptly cut the transmission chain and control the spread of the disease when patients with fever voluntarily went to the hospital. The ultimate effect of controlling the outbreak through only one intervention was not obvious. The combined community control and mask wearing, along with other interventions, could lead to rapid control of the outbreak and ultimately lower the total number of cases. More importantly, this would mitigate the impact of the outbreak on society and socioeconomics.

Introduction The aim of this study was to construct an assessment method for cross-regional transmission of coronavirus disease 2019 (COVID-19) and to provide recommendations for optimizing measures such as interregional population movements. Methods Taking Xi’an City as the example subject of this study’s analysis, a Cross-Regional-Gravitational-Dynamic model was constructed to simulate the epidemic in each district of Xi’an under three scenarios of controlled population movement (Scenario 1: no intensive intervention; Scenario 2: blocking Yanta District on December 18 and blocking the whole region on December 23; and Scenario 3: blocking the whole region on December 23). This study then evaluated the effects of such simulated population control measures. Results The cumulative number of cases for the three scenarios was 8,901,425, 178, and 474, respectively, and the duration of the epidemic was 175, 18, and 22 days, respectively. The real world prevention and control measures in Xi’an reduced the cumulative number of cases for its outbreak by 99.98% in comparison to the simulated response in Scenario 1; in contrast, the simulated prevention and control strategies set in Scenarios 2 (91.26%) and 3 (76.73%) reduced cases even further than the real world measures used in Xi’an. Discussion The constructed model can effectively simulate an outbreak across regions. Timely implementation of two-way containment and control measures in areas where spillover is likely to occur is key to stopping cross-regional transmission.

Abstract Objective: This study elaborated the natural history parameters of Delta variant, explored the differences in detection cycle thresholds (Ct) among cases.Method: Natural history parameters were calculated based on the different onset times and exposure times of the cases. Intergenerational relationships between generations of cases were calculated. Differences in Ct values of cases by gender, age, and mode of detection were analyzed statistically to assess the detoxification capacity of cases.Result: The median incubation period was 4 days; the detection time for cases decreased from 25 to 7 hours as the outbreak continued. The mean intergenerational, intergenerational infectiousness and intergenerational symptomatology were 3.6, 1.67 and 1.7 days. Among the Ct values, we found little differences in testing across companies, but there were some differences in the gender of detected genes. The Ct values continuous to decreased with age, but increased when the age was greater than 60.Conclusion: This epidemic was caused by the aggregation of factories. The effective reproduction number and real-time reproduction number were calculated using symptom intergenerational relationship (SI). And the analysis of Ct values can improve the positive detection rate and improve prevention and control measures.

Background There is still a relatively serious disease burden of infectious diseases and the warning time for different infectious diseases before implementation of interventions is important. The logistic differential equation models can be used for predicting early warning of infectious diseases. The aim of this study is to compare the disease fitting effects of the logistic differential equation (LDE) model and the generalized logistic differential equation (GLDE) model for the first time using data on multiple infectious diseases in Jilin Province and to calculate the early warning signals for different types of infectious diseases using these two models in Jilin Province to solve the disease early warning schedule for Jilin Province throughout the year. Methods Collecting the incidence of 22 infectious diseases in Jilin Province, China. The LDE and GLDE models were used to calculate the recommended warning week (RWW), the epidemic acceleration week (EAW) and warning removed week (WRW) for acute infectious diseases with seasonality, respectively. Results Five diseases were selected for analysis based on screening principles: hemorrhagic fever with renal syndrome (HFRS), shigellosis, mumps, Hand, foot and mouth disease (HFMD), and scarlet fever. The GLDE model fitted the above diseases better (0.80 ≤ R 2 ≤ 0.94, P < 0. 005) than the LDE model. The estimated warning durations (per year) of the LDE model for the above diseases were: weeks 12–23 and 40–50; weeks 20–36; weeks 15–24 and 43–52; weeks 26–34; and weeks 16–25 and 41–50. While the durations of early warning (per year) estimated by the GLDE model were: weeks 7–24 and 36–51; weeks 13–37; weeks 11–26 and 39–54; weeks 23–35; and weeks 12–26 and 40–50. Conclusions Compared to the LDE model, the GLDE model provides a better fit to the actual disease incidence data. The RWW appeared to be earlier when estimated with the GLDE model than the LDE model. In addition, the WRW estimated with the GLDE model were more lagged and had a longer warning time.

Objective: Mumps is a seasonal infectious disease, always occurring in winter and spring. In this study, we aim to analyze its epidemiological characteristics, transmissibility, and its correlation with meteorological variables. Method: A seasonal Susceptible-Exposed-Infectious/Asymptomatic-Recovered model and a next-generation matrix method were applied to estimate the time-dependent reproduction number (R-t). Results: The seasonal double peak of annual incidence was mainly in May to July and November to December. There was high transmission at the median of R-t = 1.091 (ranged: 0 to 4.393). R-t was seasonally distributed mainly from February to April and from September to November. Correlations were found between temperature (Pearson correlation coefficient [r] ranged: from 0.101 to 0.115), average relative humidity (r = 0.070), average local pressure (r = -0.066), and the number of new cases. In addition, average local pressure (r = 0.188), average wind speed (r = 0.111), air temperature (r ranged: -0.128 to -0.150), average relative humidity (r = -0.203) and sunshine duration (r = -0.075) were all correlated with R-t. Conclusion: A relatively high level of transmissibility has been found in Xiamen City, leading to a continuous epidemic of mumps. Meteorological factors, especially air temperature and relative humidity, may be more closely associated with mumps than other factors. (C) 2022 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.

Background This study aimed to explore whether the transmission routes of severe fever with thrombocytopenia syndrome (SFTS) will be affected by tick density and meteorological factors, and to explore the factors that affect the transmission of SFTS. We used the transmission dynamics model to calculate the transmission rate coefficients of different transmission routes of SFTS, and used the generalized additive model to uncover how meteorological factors and tick density affect the spread of SFTS. Methods In this study, the time-varying infection rate coefficients of different transmission routes of SFTS in Jiangsu Province from 2017 to 2020 were calculated based on the previous multi-population multi-route dynamic model (MMDM) of SFTS. The changes in transmission routes were summarized by collecting questionnaires from 537 SFTS cases in 2018–2020 in Jiangsu Province. The incidence rate of SFTS and the infection rate coefficients of different transmission routes were dependent variables, and month, meteorological factors and tick density were independent variables to establish a generalized additive model (GAM). The optimal GAM was selected using the generalized cross-validation score (GCV), and the model was validated by the 2016 data of Zhejiang Province and 2020 data of Jiangsu Province. The validated GAMs were used to predict the incidence and infection rate coefficients of SFTS in Jiangsu province in 2021, and also to predict the effect of extreme weather on SFTS. Results The number and proportion of infections by different transmission routes for each year and found that tick-to-human and human-to-human infections decreased yearly, but infections through animal and environmental transmission were gradually increasing. MMDM fitted well with the three-year SFTS incidence data (P<0.05). The best intervention to reduce the incidence of SFTS is to reduce the effective exposure of the population to the surroundings. Based on correlation tests, tick density was positively correlated with air temperature, wind speed, and sunshine duration. The best GAM was a model with tick transmissibility to humans as the dependent variable, without considering lagged effects (GCV = 5.9247E-22, R2 = 96%). Reported incidence increased when sunshine duration was higher than 11 h per day and decreased when temperatures were too high (>28°C). Sunshine duration and temperature had the greatest effect on transmission from host animals to humans. The effect of extreme weather conditions on SFTS was short-term, but there was no effect on SFTS after high temperature and sunshine hours. Conclusions Different factors affect the infection rate coefficients of different transmission routes. Sunshine duration, relative humidity, temperature and tick density are important factors affecting the occurrence of SFTS. Hurricanes reduce the incidence of SFTS in the short term, but have little effect in the long term. The most effective intervention to reduce the incidence of SFTS is to reduce population exposure to high-risk environments.

新型冠状病毒肺炎( coronavirus disease 2019,CO-VID-19 )是由新型冠状病毒( SARS-CoV-2 )所引起的,对全球公共卫生具有重大影响的潜在致命性新发传染病[1].该病的潜伏期为1 ～14 天,通常为3 ～7 天,甚至可以达到24 天[2].易感人群被SARS-CoV-2 感染后,主要症状表现为发热,咳嗽和乏力等[3].此外,该疾病主要通过呼吸道飞沫传播和接触传播,并且在相对密闭的环境中也可通过气溶胶传播[4].

Background Hand-Foot-and-Mouth-Disease (HFMD) has been widely spread in Asia, and has result in a high disease burden for children in many countries. However, the dissemination characteristics intergroup and between different age groups are still not clear. In this study, we aim to analyze the differences in the transmissibility of HFMD, in the whole population and among age groups in Shenzhen city, by utilizing mathematical models. Methods A database that reports HFMD cases in Shenzhen city from January 2010 to December 2017 was collected. In the first stage, a Susceptive-Infected-Recovered (SIR) model was built to fit data of Shenzhen city and its districts, and Reff was used to assess transmissibility in each district. In the second stage, a cross-age groups SIR model was constructed to calculate the difference in transmissibility of reported cases among three age groups of EV71 virus: 0–3 years, 3–5 years, and over 5 years which was denoted as age group 1, 2, and 3, respectively. Results From 2010 to 2017, 345,807 cases of HFMD were reported in Shenzhen city, with peak incidence in spring and autumn in Shenzhen city and most of its districts each year. Analysis of the EV71 incidence data by age group revealed that age Group 1 have the highest incidence (3.13 ×10−7–2.31 ×10−4) while age group 3 had the lowest incidence (0–3.54 ×10−5). The differences in weekly incidence of EV71 between age groups were statistically significant (t12 = 7.563, P < 0.0001; t23 = 12.420, P < 0.0001; t13 = 16.996, P < 0.0001). The R2 of the SIR model Shenzhen city population-wide HFMD fit for each region was >0.5, and P < 0.001. Reff values were >1 for the vast majority of time and regions, indicating that the HFMD virus has the ability to spread in Shenzhen city over the long-term. Differences in Reff values between regions were judged by using analysis of variance (ANOVA) (F = 0.541, P = 0.744). SiIiRi-SjIjRj models between age groups had R2 over 0.7 for all age groups and P <0.001. The Reff values between groups show that the 0–2 years old group had the strongest transmissibility (median: 2.881, range: 0.017–9.897), followed by the over 5 years old group (median: 1.758, range: 1.005–5.279), while the 3–5 years old group (median: 1.300, range: 0.005–1.005) had the weakest transmissibility of the three groups. Intra-group transmissibility was strongest in the 0–2 years age group (median: 1.787, range: 0–9.146), followed by Group 1 to Group 2 (median: 0.287, range: 0–1.988) and finally Group 1 to Group 3 (median: 0.287, range: 0–1.988). Conclusion The incidence rate of HFMD is high in Shenzhen city. In the data on the incidence of EV71 in each age group, the highest incidence was in the 0–2 years age group, and the lowest incidence was in the over 5 years age group. The differences in weekly incidence rate of EV71 among age groups were statistically significant. Children with the age of 0–2 years had the highest transmissibility.

Objective: This study elaborated the natural history parameters of Delta variant, explored the differences in detection cycle thresholds (Ct) among cases.Methods: Natural history parameters were calculated based on the different onset time and exposure time of the cases. Intergenerational relationships between generations of cases were calculated. Differences in Ct values of cases by gender, age, and mode of detection were analyzed statistically to assess the detoxification capacity of cases.Results: The median incubation period was 4 days; the detection time for cases decreased from 25 to 7 h as the outbreak continued. The average generation time (GT), time interval between transmission generations (TG) and serial interval (SI) were 3.6 +/- 2.6 days, 1.67 +/- 2.11 days and 1.7 +/- 3.0 days. Among the Ct values, we found little differences in testing across companies, but there were some differences in the gender of detected genes. The Ct values continuous to decreased with age, but increased when the age was greater than 60.Conclusion: This epidemic was started from aggregation of factories. It is more reasonable to use SI to calculate the effective reproduction number and the time-varying reproduction number. And the analysis of Ct values can improve the positive detection rate and improve prevention and control measures. (c) 2022 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Objective: To describe the epidemiological characteristics of norovirus outbreaks in Jiangsu Province, utilize the total attack rate (TAR) and transmissibility (Runc) as the measurement indicators of the outbreak, and a statistical difference in risk factors associated with TAR and transmissibility was compared. Ultimately, this study aimed to provide scientific suggestions to develop the most appropriate prevention and control measures. Method: We collected epidemiological data from investigation reports of all norovirus outbreaks in Jiangsu Province from 2012 to 2018 and performed epidemiological descriptions, sequenced the genes of the positive specimens collected that were eligible for sequencing, created a database and calculated the TAR, constructed SEIAR and SEIARW transmission dynamic models to calculate Runc, and performed statistical analyses of risk factors associated with the TAR and Runc. Results: We collected a total of 206 reported outbreaks, of which 145 could be used to calculate transmissibility. The mean TAR in was 2.6% and the mean Runc was 12.2. The epidemiological characteristics of norovirus outbreaks showed an overall increasing trend in the number of norovirus outbreaks from 2012 to 2018; more outbreaks in southern Jiangsu than northern Jiangsu; more outbreaks in urban areas than in rural areas; outbreaks occurred mostly in autumn and winter. Most of the sites where outbreaks occurred were schools, especially primary schools. Interpersonal transmission accounted for the majority. Analysis of the genotypes of noroviruses revealed that the major genotypes of the viruses changed every 3 years, with the GII.2 [P16] type of norovirus dominating from 2016 to 2018. Statistical analysis of TAR associated with risk factors found statistical differences in all risk factors, including time (year, month, season), location (geographic location, type of settlement, type of premises), population (total number of susceptible people at the outbreak site), transmission route, and genotype (P < 0.05). Statistical analysis of transmissibility associated with risk factors revealed that only transmissibility was statistically different between sites. Conclusions: The number of norovirus outbreaks in Jiangsu Province continues to increase during the follow-up period. Our findings highlight the impact of different factors on norovirus outbreaks and identify the key points of prevention and control in Jiangsu Province.

Objectives Despite the adoption of a new childhood immunization program in China, the incidence of mumps remains high. This study aimed to describe the epidemiological characteristics of mumps in Jilin Province from 2005 to 2019 and to assess the transmissibility of mumps virus among the whole population and different subgroups by regions and age groups. Methods The Non-age-specific and age-specific Susceptible–Exposed–Pre-symptomatic–Infectious–Asymptomatic–Recovered (SEPIAR) models were fitted to actual mumps incidence data. The time-varying reproduction number ( R t ) was used to evaluate and compare the transmissibility. Results From 2005 to 2019, a total of 57,424 cases of mumps were reported in Jilin Province. The incidence of mumps was the highest in people aged 5 to 9 years (77.37 per 100,000). The two SEPIAR models fitted the reported data well ( P < 0.01). The median transmissibility ( R t ) calculated by the two SEPIAR models were 1.096 (range: 1.911 × 10 −5 –2.192) and 1.074 (range: 0.033–2.114) respectively. The age-specific SEPIAR model was more representative of the actual epidemic of mumps in Jilin Province from 2005–2019. Conclusions For mumps control, it is recommended that mumps-containing vaccines (MuCV) coverage be increased nationwide in the 5–9 years age group, either by a mumps vaccine alone or by a combination of vaccines such as measles-mumps-rubella (MMR) vaccine. The coverage of vaccines in Jilin Province should be continuously expanded to establish solid immunity in the population. China needs to redefine the optimal time interval for MuCV immunization.

目的 通过对2007-2018吉林省肾综合征出血热病例进行流行特征描述,使用时间序列分析,预测吉林省未来的肾综合征出血热发病趋势.方法 通过建立ARIMA模型,对2007-2018年间吉林省肾综合征出血热发病数进行拟合,使用2019-2021年发病数与预测结果之间进行拟合优度检验来验证拟合效果.结果 2007-2018年间,吉林省共上报肾综合征出血热8 844例.总体来说吉林省肾综合征出血热发病率呈现缓慢下降趋势,时间序列分析结果为:ARIMA(1,0,0)(0,1,2)12较好地拟合和预测吉林省肾综合征出血热发病数(R2=0.66,P＜0.05).2019年至2021年预测肾综合征出血热发病数分别为510人、449人和513人.将2019-2021年HFRS实际病例数并与ARIMA模型预测数据进行比较,计算相关系数R2=0.85,P＜0.05.结论 ARIMA模型能较好地拟合和预测吉林省HFRS发病数.

Background The epidemiological characteristics and transmissibility of Coronavirus Disease 2019 (COVID-19) may undergo changes due to the mutation of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) strains. The purpose of this study is to compare the differences in the outbreaks of the different strains with regards to aspects such as epidemiological characteristics, transmissibility, and difficulties in prevention and control. Methods COVID-19 data from outbreaks of pre-Delta strains, the Delta variant and Omicron variant, were obtained from the Chinese Center for Disease Control and Prevention (CDC). Case data were collected from China's direct-reporting system, and the data concerning outbreaks were collected by on-site epidemiological investigators and collated by the authors of this paper. Indicators such as the effective reproduction number (Reff), time-dependent reproduction number (Rt), rate of decrease in transmissibility (RDT), and duration from the illness onset date to the diagnosed date (DID)/reported date (DIR) were used to compare differences in transmissibility between pre-Delta strains, Delta variants and Omicron variants. Non-parametric tests (namely the Kruskal-Wallis H and Mean-Whitney U tests) were used to compare differences in epidemiological characteristics and transmissibility between outbreaks of different strains. P < 0.05 indicated that the difference was statistically significant. Results Mainland China has maintained a “dynamic zero-out strategy” since the first case was reported, and clusters of outbreaks have occurred intermittently. The strains causing outbreaks in mainland China have gone through three stages: the outbreak of pre-Delta strains, the outbreak of the Delta variant, and outbreaks involving the superposition of Delta and Omicron variant strains. Each outbreak of pre-Delta strains went through two stages: a rising stage and a falling stage, Each outbreak of the Delta variant and Omicron variant went through three stages: a rising stage, a platform stage and a falling stage. The maximum Reff value of Omicron variant outbreaks was highest (median: 6.7; ranged from 5.3 to 8.0) and the differences were statistically significant. The RDT value of outbreaks involving pre-Delta strains was smallest (median: 91.4%; [IQR]: 87.30–94.27%), and the differences were statistically significant. The DID and DIR for all strains was mostly in a range of 0–2 days, with more than 75%. The range of duration for outbreaks of pre-Delta strains was the largest (median: 20 days, ranging from 1 to 61 days), and the differences were statistically significant. Conclusion With the evolution of the virus, the transmissibility of the variants has increased. The transmissibility of the Omicron variant is higher than that of both the pre-Delta strains and the Delta variant, and is more difficult to suppress. These findings provide us with get a more clear and precise picture of the transmissibility of the different variants in the real world, in accordance with the findings of previous studies. Reff is more suitable than Rt for assessing the transmissibility of the disease during an epidemic outbreak.

Despite the adoption of a national immunization program in China, the incidence of mumps remains high. This study aimed to describe the epidemiological characteristics, including the time, region, occupation, and age, of mumps in Wuhan from 2005 to 2018 and to evaluate its transmissibility. In this study, the susceptible–exposed–infectious–asymptomatic–recovered (SEIAR) model fitted the actual incidence data of mumps. The effective reproduction number (Rt) was used to evaluate and compare the transmission capacity in different areas. From 2005 to 2018, there were 36,415 cases. The incidence of mumps was highest among people aged 5–10 years (460.02 per 100,000). The SEIAR model fitted the reported mumps data well (P < 0.01). The median transmissibility (Rt) was 1.04 (range = 0–2.50). There were two peak spreads every year (from March to May and from October to December). The Rt peak always appeared in the first 2 months of the peak incidence rate. The peak time of the epidemic spread of mumps was 1–2 months earlier than the peak incidence rate. The prevention and control measures of vaccination for children aged 5–10 years should be taken before the peak transmission capacity each year, 2 months before the peak of the outbreak, to reduce the spread of mumps.

Background: With the strength intervention of China, the outbreak of Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) had a great control effect. The measures may influence the development and progression of others infectious diseases. Method: The data of daily coronavirus virus disease 2019 (COVID-19) confirmed cases from January 3, 2020 to April 30, 2020 and natural focal disease cases from January, 2005 to April, 2020 were collected from Jiangsu Provincial Center for Disease Control and Prevention (Jiangsu Provincial CDC). We describe and compare the data of natural focal diseases from January to April, 2020 with the same months from 2015 to 2019 in the four aspects: trend of incidence, regional, age and sex distribution. Nonparametric tests were used to analyzed to the difference between the duration from onset of illness to date of diagnosis of natural focal diseases and the same period of the previous year. Results: The incidence of malaria in February (0.9 per 10,000,000 people), March (0.3 per 10,000,000 people) and April (0.1 per 10,000,000 people) 2020 less than the lower limit for range of February (1.6-4.5 per 10,000,000 people), March (0.8-3.3 per 10,000,000 people) and April (1.0-2.9 per 10,000,000 people) from 2015 to 2019 respectively. The incidence of brucellosis in February was 0.9 (per 10,000,000 people), less than the lower limit for the range from 2015 to 2019 (1.6-4.5 per 10,000,000 people). The incidence of hemorrhagic fever (HF) in March was 1.0 (per 10,000,000 people), less than the lower limit for the range from 2015 to 2019 (1.4-2.6 per 10,000,000 people). However, the incidence of Severe Fever with Thrombocytopenia Syndrome (SEFT) in March was 0.3 (per 10,000,000 people), higher than the upper limit for the range from 2015 to 2019 (0.0-0.1 per 10,000,000 people). Furthermore, we respectively observed the incidence with various degree of reduction in male, 20-60 years old and both rural and urban areas. Conclusions: In Jiangsu province, the incidence of natural focal diseases decreased during the outbreak of COVID-19 in 2020, especially malaria, HF and SEFT. The impact of interventions were felt most by male individuals within the age group of 20-50 years. The interventions for COVID-19 may control the epidemics of natural focal diseases.