The differences in social contacts of age groups led to the variations of infection scales and requirements on hospital beds, and even the changes of the scales of severe infection and death during COVID-19 era. To figure out the transmission mechanism of age group, we proposed a multi-age group epidemic model with social contacts in this paper. Then, the basic reproduction numbers for the total population and the specific age group were respectively derived, in which the intra-average contact number for the specific age group determined the basic reproduction number therein. Meanwhile, the global stability for disease-free equilibrium point as well as the uniform persistence around endemic equilibrium point were extensively discussed. Furthermore, based on surveillance data from Fujian Provincial Center for Disease Control and Prevention, the simulation results showed that the high susceptibility to infection implied the high-risk of the specific age group. Especially, for the high-risk age group, the impacts of social contacts under three scenarios were significant. As a consequence, the local government was suggested to decline social contacts by closing the massive activities to avoid the shortage of hospital beds and the emergence of medical runs.

Since brucellosis causes harms and losses to sheep and human populations in the cities of Northern and Northwest China, we establish a cross-species brucellosis model with age-structure and bilinear incidences to characterize brucellosis transmission mechanism in this study. Firstly, the basic reproduction number, the disease-free and endemic equilibrium points of the brucellosis model are obtained. Then, the stabilities of two equilibrium points are proved by Routh-Hurwitz Criterion and LaSalle's Invariance Principle. Precisely, the disease-free equilibrium point is locally and globally asymptotically stable with R0 < 1; and the endemic equilibrium point is globally asymptotically stable with R0 > 1. Further, the 2017-2023 monthly brucellosis surveillance data from Jinzhou CDC are fitted by the least squares method and EpiSIX, showing that the values of basic reproduction numbers keep high consistency with the known results. The numerical simulations indicate that the reduction of brucellosis transmission risks depend on the decreases of direct transmission rates and recruitment rate, and the increases of culling rate and vaccination rate. Finally, the 2024-2030 yearly tendency predictions under two scenarios indicate that quadruple-control measure provides the extreme brucellosis transmission risks, compared with those from three-type control measures. As a consequence, for the local farmers and policy-makers, some suggestions are proposed to suppress the brucellosis infectious scales for the cities with similar sheep breeding patterns and geographical locations to Jinzhou on the Chinese mainland.

Background World Health Organization recommends that the individuals with HIV infection take HIV detection as early as possible to avoid the potential transmission risk in the community, because HIV infection often exhibit no any symptoms and being neglected by the individuals at the acute phase. In China, a series of policies relating to HIV detection have been announced by the Chinese Center for Disease Control and Prevention for effectively controlling the HIV/AIDS infection scale. Methods The next generation matrix method is governed to derive the basic reproduction number of SIDMA model with HIV detection in this study. The least squares method is used to perform the optimal fitting against the surveillance data of HIV/AIDS. The sensitivity index and partial rank correlation coefficients are used to investigate the impacts of key parameters on the HIV/AIDS incidence. The ARIMA model method is applied to predict the gender and age distributions of the Fujian HIV/AIDS epidemics. The Gini index method is for the spatial heterogeneity of all diagnosed cases. Results The numerical simulation results show that the HIV/AIDS incidence depends on two significant parameters: detection rate and effective contact rate, and that basic reproduction number relies on effective contact rate. This study reveals that the long awareness delay extends the infection scale and prevalence risk of HIV/AIDS, and that the spatial heterogeneity of diagnosed cases in nine cities of Fujian Province is relatively uniform. The 2023-2030 tendency predictions with scenarios indicate that detection rate of SIDMA model is most critical for the prevalence of the Fujian HIV/AIDS epidemics. The gender and age predictions by ARIMA model indicate that females and 60 years old and over face the potential high HIV infection risks. Conclusions The HIV detection rate is the most important contributor of SIDMA model for suppressing the HIV/AIDS incidence. The declining trend of basic reproduction number of SIDMA model in five phases indicates that HIV detection in Fujian Province have achieved remarkable achievements. The 2023-2030 tendency predictions of the Fujian HIV/AIDS epidemics provide the estimations with low-level incidence, meeting the control goal from the Chinese government. The four insights are recommended to the policy-makers and the local governments for fighting against the HIV/AIDS prevalence.

The prompt and massive detection of the community population with HIV is beneficial to the early diagnosis and helps to determine the main tendency of HIV/AIDS transmission from the perspective of public health and policy makers. In this study, an SIDMA (Susceptible-Infected-Diagnosed-Monitored-AIDS) compartmental model with HIV detection is proposed by using Holling type II functional response. The slow average handling time in HIV detection is taken into account. We first derive the basic reproduction number of the SIDMA model using the next generation matrix method. Then, the global stabilities for disease-free equilibrium point, and boundary equilibrium point are proved under moderate conditions. The research results show that the threshold of global stabilities increases with the monitoring rate. Alternatively, given that the average handling time of HIV detection is fast enough, the research results explore that the underestimation for the threshold of the global stabilities usually exists. This study reveals that positive medical interventions for the community population with HIV improve the life quality through the enhancement of the monitoring rate, also finds that prevalence situation of the community population with HIV is under control.

This study, which demonstrates that the single-population Susceptible-Exposed-Infectious-Recovered (SEIR) model is also applicable to the assessment and prediction of vector-borne infectious disease outbreaks, provides a reliable model tool for the future prevention and control of vector-borne unknown (X) epidemics. One of the key contributions is the identification of a suitable interpretation of the model parameters. The EpiSIX prediction system, via application of a single SEIR model, was used to fit and analyse the 2025 Foshan City chikungunya fever epidemic data and the 2024-2025 dengue fever epidemics data from Guangdong Province. The results showed that the average serial interval of both fevers was approximately 11 days. The estimated basic reproduction number (R0) was around 6.0 for the chikungunya fever epidemic in Foshan City and approximately 4.0 and 3.0 for the 2024 and 2025 dengue fever epidemics in Guangdong Province, respectively. An additional prediction of the development trend of the ongoing 2025 dengue fever epidemic in Guangdong Province indicated that the final number of infections would range between 3400 and 6000 cases. Finally, a comparison between the uncontrolled developments of the omicron epidemic (with an average serial interval of 4 days) and the chikungunya fever epidemic (with an average serial interval of 11 days, 2.75 times that of omicron) under the same R0 value (5.60) showed that the omicron epidemic would last for 50 days, while the chikungunya fever epidemic would persist for 120 days. Theoretically, the pressure of the former on medical resources would be 2.5 times that of the latter. (c) 2026 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-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Understanding the hidden transmission mechanism of monkeypox epidemics is essential to avoid the local or global prevalence via the sexual transmission route, the direct contact transmission route and the aerosol transmission route. First of all, we establish modified model with three transmission routes to characterize the transmission dynamics of monkeypox epidemics, of which the basic reproduction number of modified model is derived via the next-generation matrix method, the local and global stabilities of equilibrium points are explored by the Routh-Hurwitz criterion and LaSalle's invariant principle, and the existence and the expressions of the optimal controls are derived by the Pontryagin's maximum principle. Then, the numerical analysis is performed with respect to the optimal fittings, the estimation of the basic reproduction number, the global sensitivity analysis and the cost-effectiveness analysis. More precisely, the weekly surveillance data of the Democratic Republic of the Congo from 2022 to 2025 are carried out for the optimal fittings of modified model. The basic reproduction number of 2022-2025 monkeypox outbreak is estimated from 1.05 to 1.81. The sensitive parameters of modified model are chosen by using Partial Rank Correlation Coefficients to estimate the cumulative infection scales. The cost-effectiveness analysis points out that the combined strategy yields the smallest infection scale, and that the treatment strategy is the most cost-effective strategy. It is recommended to strengthen sexual health awareness for high-risk groups to optimize ventilation and air purification in high-risk environments, and to ensure comprehensive and timely treatment for infected individuals, against the increase of cumulative infection scale of monkeypox epidemics.

The unaware HIV-infected population usually bring the cryptic transmission risk in the com-munity. Testing the unaware IIIV-infected population becomes a significant approach for controlling cryptic transmission risk of HIV/AIDS, because the testing results provide unaware IIIV-infected population with infection statuses and undertaking interventions. To characterize the impacts of HIV testing on cumulative diagnosed scale of IIIV/AIDS, we propose a cryptic transmission model of HIV/AIDS with nonlinear testing in the heterosexual and homosexual populations. Theoretically, the basic reproduction number R-0 for the total population is calculated by the next generation matrix method, which takes the maximum of the basic reproduction number R-0(m) for the homosexual population, and the basic reproduction number R-0(f) for the heterosexual population. Under different threshold conditions, the globally asymptotic stabilities of disease-free, boundary and endemic equilibrium points are derived, by constructing Lyapunov function and applying the LaSalle's invariance principle. In other words, when R-0(m) < 1 and R-0(f) < 1 hold, HIV/AIDS is extinct in the total population. When R-0(m)> 1 > R-0(f) is valid, HIV/prevalent in the homosexual population. When R-0(f) > 1 > R-0(m) HIV/AIDS is prevalent in the heterosexual population. When R-0(m )> 1 and R-0(f )>1 hold, HIV/AIDS is prevalent in the total population. Numerically, the fitting results show that the heterosexual population contribute to the majority of IIIV/AIDS epidemics of Fujian Province from 2012 to 2022, and the simulation results for four testing scenarios (testing-free, male-testing, female-testing, male-and-female testing) reveal that HIV testing for undiagnosed male and female populations largely reduces the current infection scale and the cryptic transmission risk. Especially, the enhancement of HIV testing for undiagnosed female population significantly suppresses cumulative diagnosed scale. The prediction results show that, as of the end of 2035, the continuous enhancement of HIV testing for undiagnosed female and male populations contributes to the less cumulative diagnosed scale of HIV/AIDS, and the 95% diagnostic detection objective of Fujian Province will be achieved ahead of schedule.

A generalized bloodborne hepatitis model with two control measures was proposed to describe the community transmission features of HBV and HCV of Fujian Province in this study. For the susceptible-acute-chronic-treated-recovered model, the basic reproduction number of SACTR model was first investigated by the next-generation matrix method, the global stabilities of disease-free equilibrium point and endemic equilibrium point were investigated by governing Lyapunov functions. Meanwhile, the expressions of the optimal control were derived by using Pontryagin's Maximum Principle. Then, the 2004-2022 monthly surveillance data of bloodborne hepatitis from Fujian Province were used to perform the data fittings, and the basic reproduction numbers with piece-wise control measures were estimated. These results showed that the control measures for susceptible population were more effective than those for chronically infected population. Furthermore, the 2023-2035 tendency predictions of infection scales with baseline scenario and modified scenario were performed. As of the end of 2035, the infection scale of HBV was under low level, the infection scale of HCV almost reached elimination, which almost met the main goal of the Chinese government. Consequently, the suggestions for policymakers were given that the traces of high-risk susceptible population and the implementations of prompt control measures were the effective measures to cut down cross-regional transmission chains through the multi-province information sharing platform.

Background: Hepatitis C virus (HCV) is a bloodborne virus that causes both acute and chronic hepatitis with the severity from a mild illness to liver cirrhosis and cancer. As one of the major infectious diseases in China, the monthly surveillance data from the Fujian Provincial Center for Disease Control and Prevention shows the increasing tendency from 2004 to 2011, the stable tendency from 2012 to 2016, and the declining tendency from 2017 to 2022. The 2004-2022 HCV infection tendency of Fujian Province is affected by nation-wide main control measures of Chinese government, because no control measures for HCV are modified from 2020 to 2022 during the prevalence of COVID-19 in Fujian Province. Methods: The SEACTR (the susceptible, the exposed, the acutely infected, the chronically infected, the treated, the recovered) models with protection awareness are proposed. The next generation matrix method is used to compute basic reproduction number of toy model and dynamic analysis method is used to produce stochastic reproduction number of modified model. The least squares method and toy model are used to perform the optimal fitting against the monthly surveillance data. The positive preserving truncated EulerMaruyama method is applied in modified model for the positivity of numerical simulations. Results: The optimal fitting is performed using the monthly surveillance data provided by the Fujian Provincial Center for Disease Control and Prevention from 2004 to 2022. The sensitivities of protection efficiency and conversion rate to basic reproduction number and stochastic reproduction number are analyzed. The reproduction numbers and HCV infection scale with measures (single-measure, double-measure, triple-measure, and none- measure) are compared using toy model and modified model. The impacts of protection efficiency and conversion rate on exposed population, acutely infected population, chronically infected population, and treated population are analyzed. The tendency predictions for infected population and treated population in Fujian Province from 2023 to 2035 are conducted. Conclusions: The HCV infection scale mainly depends on both protection efficiency and conversion rate, in which protection efficiency is the most important contributor. The reproduction numbers show the declining tendencies by phases, which indicate that the prevention and control of HCV in Fujian Province has achieved a remarkable achievement. The 2023-2035 tendency predictions of HCV infection scale in Fujian Province grow slowly due to approximately 19-109 monthly infections. The overall HCV growth tendency of Fujian Province is consistent with the nation-wide elimination objective. (c) 2025 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-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

HIV testing and contact tracing facilitate early detection of HIV/AIDS infections for interrupting the hidden transmission. In this study, a susceptible-undiagnosed-diagnosed transmission model with testing and contact tracing is proposed in heterosexual and homosexual populations. The basic reproduction number, the heterosexual-transmission and homosexual-transmission reproduction numbers of the transmission model are derived by the next generation matrix method. The optimal-fitting results present that the basic reproduction number of Fujian 2012–2022 HIV/AIDS epidemics ranges from 1.93 to 2.74 by phases, which is consistent with the heterosexual-transmission reproduction number. The optimal fittings and the global sensitivity analysis show that the transmission risk mainly originates from the heterosexual contacts. The transmission risk assessments and the 2023–2035 tendency predictions are performed for HIV/AIDS prevalence in Fujian Province by scenarios. The numerical simulation results point out that the decrease of female-to-male transmission rate, the decline of proportion of active diagnosed population, and the reduction of the awareness delay, are the main contributors for declining HIV/AIDS prevalence. The 2023–2035 tendency predictions of Fujian Province reveal that, when the awareness delay is fixed, the rising trends of the infection scales caused by the transmission rates are more significant than those caused by the proportion of active diagnosed population. According to the transmission risk assessments and the tendency prediction results, several suggestions are provided to the policymakers for curbing the HIV/AIDS transmission in Fujian Province.

The innate immunity helps the individuals in the exposed compartment return into the ones in the susceptible compartment when a pathogen or virus invades the local population of having four compartments: the susceptible, the exposed, the infected and the recovered. In this study, we propose a stochastic SEIR model with innate immunity and treatment. Here, Holling type II functional responses are used to describe the saturated effects of the innate immunity and treatment. Then, we obtain the extinction of the exposed and the infected when the basic reproduction number R-0 < 1 and the exponential decline rate nu < 0 are valid. Moreover, we conclude that when innate immunity and treatment increase, the time that the exposed and the infected approach zero reduces. We also find that the deterministic SEIR model reaches extinction a bit faster than the stochastic SEIR model. Further, the persistence in the mean and stationary distribution of stochastic SEIR model are obtained under suitable conditions. Finally, the numerical investigations with two methods and a case study of Fuzhou COVID-19 epidemic of 2022 are discussed.

The impacts of viral virulence and its evolution on transmission dynamics are important for the public and the policymakers during the spread of infectious diseases. To reveal the impacts of viral virulence evolution on transmission dynamics within the population, we formulate a coupled SISv model with viral virulence, in which transmission rate and disease-induced death rate are set as functions of viral virulence. The dynamic analysis for SIS model and SIS-v model are extensively explored within the symptom-dependent community against viral virulence evolution. Precisely, the expressions of basic reproduction numbers for two models are derived by the next generation matrix method, the existence and stabilities of equilibrium points are then derived by Routh Hurwitz criterion and LaSalle's invariance principle. By the adaptive dynamics method, the results reveal that when the asymptomatic boundary equilibrium point is globally asymptotically stable, the mutant virus could invade the population with resident virus under certain conditions, and the globally asymptotically stable viral virulence is the evolutionary singularity that maximizes both the invasion fitness and the absolute fitness for mutant virus. When the symptomatic boundary equilibrium point is globally asymptotically stable, the conclusion is the same. Furthermore, the numerical simulations with respect to viral virulence are performed using SIS model and surveillance data. The corresponding results show that SARS-CoV-2 virulence is relaxed, when the evolution starts from wild strain to Delta strain and further to Omicron strain. The increase of viral virulence contributes to the enhancement of infection scale. While, the decrease of viral virulence contributes to the decline of basic reproduction number. The invasion fitness of mutant virus obeys the increasing tendency with the enhancement of viral virulence, until the invasion fitness reaches the maximum. The main results provide three significant insights for the public and the policymakers of local government to fight against the spread of infectious diseases: the features of viral virulence evolution are helpful to the public against the newly emerging strains; the non-pharmacological interventions of the local government effectively decline basic reproduction number for the asymptomatic individuals and the symptomatic individuals within the key population; when the key population consists of the asymptomatic individuals, the local government should focus on the prompt nucleic acid screening against the spread of epidemic; when the key population consists of the symptomatic individuals, the local government should strengthen isolation measures for the symptomatic individuals.

The impacts of strain evolution on transmission dynamics are important for the public and the policymakers during the spread of infectious diseases. A varying-strain model is proposed to analyze the small-scale and short-duration epidemics. First, the expression of basic reproduction number is obtained by next generation matrix method. Then, the stabilities of equilibrium points are derived by Routh-Hurwitz criterion and LaSalle's invariant principle. Further, combining the official surveillance data, the impacts of infection scales are investigated. Meanwhile, the sensitivity analysis for basic reproduction number and peaks of infected individuals are conducted. The results of this study provide significant insights for the policymakers controlling small-scale and short-duration epidemics.

We propose a stochastic HCV model with protection awareness and exposed-acute-chronic phases in this study. First of all, we show that the stochastic HCV model admits a unique global positive solution for any given positive initial values. Then, we verify that HCV model has a unique stationary distribution under the sufficient criterion R-0(s )> 1, which indicates that HCV transmission undergoes the persistence in the long term. Furthermore, we derive the sufficient conditions for HCV extinction under the condition R-0(e )< 1. As a consequence, we derive the relationships among the stochastic persistence index R-0(s), the stochastic extinction index R-0(e ) and the threshold (the basic reproduction number R0) of the model without fluctuations. The condition R-0 > R-0(s )> 1 reveals that the existence of the white noises triggers the less stochastic persistence index. While, the condition R-0 < R-0(e )< 1 reveals that, when the intensities of the white noises are enhanced, the value R-0(e ) triggers the stochastic extinction.

Syphilis is a blood-borne disease with multiple hidden-transmission stages caused by Treponema pallidum, and most infected individuals are asymptomatic as reported by the World Health Organization. This study establishes a Susceptible-Exposed-Infected-Latent-Recovered-Susceptible syphilis model with the nonlinear incidence and early latent stage incorporating the psychological effect. Firstly, the basic reproduction number of the SEILRS syphilis model is derived using the next generation matrix method. Then, the local asymptotic stability of the syphilis-free equilibrium point is proved. The global asymptotic stabilities of the syphilis-free equilibrium point and an endemic equilibrium point are shown by LaSalle’s invariance principle. Further, the key parameters of the SEILRS syphilis model are estimated by the least squares method against the surveillance data of Fujian Province, China. The numerical simulation demonstrates that the changes of transmission rate in the early latent stage, treatment rate in the secondary stage and psychological effect in the early latent stage present the significant influences on the infection scale of syphilis. The 2023-2030 tendency predictions of the infection scale with scenarios indicate that the transmission rates are most critical for the prevalence of syphilis. As a consequence, to more effectively reduce the transmission rates of syphilis, it is recommended to enhance testing and screening for high-risk groups, to ensure the effective and complete treatment for infected individuals in the secondary stage, and to vigorously publicize the asymptomatic but infectious characteristics of infected individuals in the early latent stage.

The epidemiological characteristics and distributions of two epidemics in Fujian Province of Southeast China were attributed to the complex interactions among variant, host, and non-pharmaceutical interventions (NPIs). All reported cases in the Putian epidemic (September 8–October 2, 2021, Delta variant B.1.617.2) and Fuzhou epidemic (October 22–November 18, 2022, Omicron variant BA.5.2) were classified by sex, age group, occupation, and location in this study. Using surveillance data from the Fujian Provincial Center for Disease Control and Prevention, we established a virus-oriented SVEIR (Susceptible–Vaccinated–Exposed–Infected–Recovered) model to investigate the dynamic evolution features of these two variants and the effects of NPIs. The optimal simulations were carried out with variants and scenario investigations. The scenario investigations showed that NPIs significantly reduced the transmission risk and infection scales of COVID-19, and that the Omicron variant was more infectious than the Delta variant. Moreover, the dynamic investigations revealed the increasing tendencies from Delta to Omicron, such as the basic reproduction number, infection rate, percentage of high-risk cases, and the growth rate. Decreasing tendencies were also identified, such as the average recovery period, the awareness delay, and the percentage of symptomatic cases. This study highlighted that NPIs played critical roles in successfully containing the two epidemics. Such interventions are strongly recommended to public health policymakers.

This work develops a novel approximation for a class of superlinear stochastic Kolmogorov equations with positive global solutions. On the one hand, most existing explicit methods that work for the superlinear stochastic differential equations (SDEs), e.g. various modified Euler–Maruyama (EM) methods, fail to preserve positivity of the solution. On the other hand, methods that preserve positivity are mostly implicit, or fail to cope with the multi-dimensional scenario. This work aims to construct an advanced numerical method which is not only naturally structure preserving but also cost effective. A strong convergence framework is then developed with an almost optimal convergence rate of order arbitrarily close to 1 / 2. To make the arguments concise, we elaborate our theory with the generalised stochastic Lotka–Volterra model, though the method is applicable to a wide bunch of multi-dimensional superlinear stochastic Kolmogorov systems in various fields including finance and epidemiology.

In this study, we proposed two, symptom-dependent, HIV/AIDS models to investigate the dynamical properties of HIV/AIDS in the Fujian Province. The basic reproduction number was obtained, and the local and global stabilities of the disease-free and endemic equilibrium points were verified to the deterministic HIV/AIDS model. Moreover, the indicators $ R_0^s $ and $ R_0^e $ were derived for the stochastic HIV/AIDS model, and the conditions for stationary distribution and stochastic extinction were investigated. By using the surveillance data from the Fujian Provincial Center for Disease Control and Prevention, some numerical simulations and future predictions on the scale of HIV/AIDS infections in the Fujian Province were conducted.

We propose single-species population models with the psychological effects and time delay in a toxicant environment in this study, of which the concentrations of toxicant nonlinearly affect the density of adults, linearly affect the density of juveniles. The models, consisting of a system of stochastic differential equations, govern the dynamics of juveniles and adults, as well as the concentrations of toxicant in the environment and organisms. First of all, the existence and uniqueness of the global solution to the models are derived, the sufficient conditions of the extinction and the time that the densities of adults and juveniles approach zero are investigated. Further, the sufficient conditions for the weak persistence in the mean are obtained around the pollution-free equilibrium point, and the stochastic permanence of adults and juveniles occurs around the pollution equilibrium points under moderate conditions. As a consequence, the corresponding numerical simulations reveal that higher psychological effects and less time delay create larger densities of juveniles and adults in the sense of weak persistence and stochastic permanence, and that less fluctuations of white noises and less psychological effects produce the earlier extinction time for adults and juveniles.

The differences of SARS-CoV-2 variants brought the changes of transmission characteristics and clinical manifestations during the prevalence of COVID-19. In order to explore the evolution mechanisms of SARS-CoV-2 variants and the impacts of variant evolution, the classic SIR (Susceptible-Infected-Recovered) compartment model was modified to a generalized SVEIR (Susceptible-Vaccinated-Exposed-Infected-Recovered) compartment model with age-group and varying variants in this study. By using of the SVEIR model and least squares method, the optimal fittings against the surveillance data from Fujian Provincial Center for Disease Control and Prevention were performed for the five epidemics of Fujian Province. The main epidemiological characteristics such as basic reproduction number, effective reproduction number, sensitivity analysis, and cross-variant scenario investigations were extensively investigated during dynamic zero-COVID policy. The study results showed that the infectivities of the variants became fast from wild strain to the Delta variant, further to the Omicron variant. Meanwhile, the cross-variant investigations showed that the average incubation periods were shortened, and that the infection scales quickly enhanced. Further, the risk estimations with the new variants were performed without implements of the non-pharmaceutical interventions, based on the dominant variants XBB.1.9.1 and EG.5. The results of the risk estimations suggested that non-pharmaceutical interventions were necessary on the Chinese mainland for controlling severe infections and deaths, and also that the regular variant monitors were still workable against the aggressive variant evolution and the emergency of new transmission risks in the future.