Modeling outbreaks of COVID-19 in China: The impact of vaccination and other control measures on curbing the epidemic.

This study aims to examine the development trend of COVID-19 in China and propose a model to assess the impacts of various prevention and control measures in combating the COVID-19 pandemic. Using COVID-19 cases reported by the National Health Commission of China from January 2, 2020, to January 2, 2022, we established a Susceptible-Exposed-Infected-Asymptomatic-Quarantined-Vaccinated-Hospitalized-Removed (SEIAQVHR) model to calculate the COVID-19 transmission rate and Rt effective reproduction number, and assess prevention and control measures. Additionally, we built a stochastic model to explore the development of the COVID-19 epidemic. We modeled the incidence trends in five outbreaks between 2020 and 2022. Some important features of the COVID-19 epidemic are mirrored in the estimates based on our SEIAQVHR model. Our model indicates that an infected index case entering the community has a 50%-60% chance to cause a COVID-19 outbreak. Wearing masks and getting vaccinated were the most effective measures among all the prevention and control measures. Specifically targeting asymptomatic individuals had no significant impact on the spread of COVID-19. By adjusting prevention and control parameters, we suggest that increasing the rates of effective vaccination and mask-wearing can significantly reduce COVID-19 cases in China. Our stochastic model analysis provides a useful tool for understanding the COVID-19 epidemic in China.

Hysteresis effects of different levels of storm flooding on susceptible enteric infectious diseases in a central city of China.

BACKGROUND: Recently, attention has focused on the impact of global climate change on infectious diseases. Storm flooding is an extreme weather phenomenon that not only impacts the health of the environment but also worsens the spread of pathogens. This poses a significant challenge to public health security. However, there is still a lack of research on how different levels of storm flooding affect susceptible enteric infectious diseases over time. METHODS: Data on enteric infectious diseases, storm flooding events, and meteorology were collected for Changsha, Hunan Province, between 2016 and 2020. The Wilcoxon Rank Sum Test was used to identify the enteric infectious diseases that are susceptible to storm flooding. Then, the lagged effects of different levels of storm flooding on susceptible enteric infectious diseases were analyzed using a distributed lag nonlinear model. RESULTS: There were eleven storm flooding events in Changsha from 2016 to 2020, concentrated in June and July. 37,882 cases of enteric infectious diseases were reported. During non-flooding days, the daily incidence rates of typhoid/paratyphoid and bacillary dysentery were 0.3/100,000 and 0.1/100,000, respectively. During flooding days, the corresponding rates increased to 2.0/100,000 and 0.8/100,000, respectively. The incidence rates of both diseases showed statistically significant differences between non-flooding and flooding days. Correlation analysis shows that the best lags for typhoid/paratyphoid and bacillary dysentery relative to storm flooding events may be 1 and 3 days. The results of the distributed lag nonlinear model showed that typhoid/paratyphoid had the highest cumulative RR values of 2.86 (95% CI: 1.71-4.76) and 8.16 (95% CI: 2.93-22.67) after 4 days of general flooding and heavy flooding, respectively; and bacillary dysentery had the highest cumulative RR values of 1.82 (95% CI: 1.40-2.35) and 3.31 (95% CI: 1.97-5.55) after 5 days of general flooding and heavy flooding, respectively. CONCLUSIONS: Typhoid/paratyphoid and bacillary dysentery are sensitive enteric infectious diseases related to storm flooding in Changsha. There is a lagging effect of storm flooding on the onset of typhoid/paratyphoid and bacillary dysentery, with the best lagging periods being days 1 and 3, respectively. The cumulative risk of typhoid/paratyphoid and bacillary dysentery was highest at 4/5 days lag, respectively. The higher of storm flooding, the higher the risk of disease, which suggests that the authorities should take appropriate preventive and control measures before and after storm flooding.

Spatial heterogeneity of socio-economic determinants of typhoid/paratyphoid fever in one province in central China from 2015 to 2019.

BACKGROUND: Typhoid fever and paratyphoid fever are one of the most criticial public health issues worldwide, especially in developing countries. The incidence of this disease may be closely related to socio-economic factors, but there is a lack of research on the spatial level of relevant determinants of typhoid fever and paratyphoid fever. METHODS: In this study, we took Hunan Province in central China as an example and collected the data on typhoid and paratyphoid incidence and socio-economic factors in 2015-2019. Firstly spatial mapping was made on the disease prevalence, and again using geographical probe model to explore the critical influencing factors of typhoid and paratyphoid, finally employing MGWR model to analysis the spatial heterogeneity of these factors. RESULTS: The results showed that the incidence of typhoid and paratyphoid fever was seasonal and periodic and frequently occurred in summer. In the case of total typhoid and paratyphoid fever, Yongzhou was the most popular, followed by Xiangxi Tujia and Miao Autonomous Prefecture, Huaihua and Chenzhou generally focused on the south and west. And Yueyang, Changde and Loudi had a slight increase trend year by year from 2015 to 2019. Moreover, the significant effects on the incidence of typhoid and paratyphoid fever from strong to weak were as follows: gender ratio(q = 0.4589), students in ordinary institutions of higher learning(q = 0.2040), per capita disposable income of all residents(q = 0.1777), number of foreign tourists received(q = 0.1697), per capita GDP(q = 0.1589), and the P values for these factors were less than 0.001. According to the MGWR model, gender ratio, per capita disposable income of all residents and Number of foreign tourists received had a positive effect on the incidence of typhoid and paratyphoid fever. In contrast, students in ordinary institutions of higher learning had a negative impact, and per capita GDP shows a bipolar change. CONCLUSIONS: The incidence of typhoid and paratyphoid fever in Hunan Province from 2015 to 2019 was a marked seasonality, concentrated in the south and west of Hunan Province. Attention should be paid to the prevention and control of critical periods and concentrated areas. Different socio-economic factors may show other directions and degrees of action in other prefecture-level cities. To summarize, health education, entry-exit epidemic prevention and control can be strengthened. This study may be beneficial to carry out targeted, hierarchical and focused prevention and control of typhoid fever and paratyphoid fever, and provide scientific reference for related theoretical research.

The development trend of influenza in China from 2010 to 2019.

In this study, we quantify and evaluate the transmission capacity of different types of influenza, and evaluate the flu vaccination effect. Taking the influenza cases reported by the National Influenza Center of China from 2010 to 2019 as the research object (http://www.chinaivdc.cn/cnic), we established the SEIABR model to calculate the influenza infection rate and R0 for each year from 2010 to 2019, and calculate the influenza A and B influenza infection rates. We further added vaccination measures to the SEIABR model, and analysis the impact of different vaccination rates on the spread of influenza. We find that the range of ß(infection rate) is 6.03×10-10 to 9.66×10-10, and the average is 7.95±1.27×10-10, the range of R0 is .98 to 1.47, and the average is 1.21. Simulation result suggest that vaccine coverage needed to reach 60%-80% to control the spread of influenza virus in China when the vaccine effectiveness was 20%-40%. When the vaccine effectiveness is 40%-60%, vaccine coverage needs to reach 40%-60% to control the spread of influenza virus in China. In China, the infection rate of influenza A is higher than influenza B, to better control the spread of the flu virus, we suggest that we also need to increase the number of people vaccinated or improve the efficiency of vaccines(the current vaccination coverage is probably less than 20%).

Assess transmissibility of different influenza subtypes: Based on a SEIABR model.

OBJECTIVE: Influenza is a worldwide public health problem which causes a serious economic and health burden. In order to provide a scientific basis for improving the prevention and control level of influenza, using dynamic model to evaluate the infection rates of influenza different subtypes from 2010 to 2019 in China. METHODS: This article established SEIABR model based on influenza cases reported by China National Influenza Center from 2010 to 2019. And calculated the transmission rate and Re by combined the natural birth rate, natural death rate, infectious rate, proportion of asymptomatic patients, proportion of untreated patients, recovery rate and fatality rate. RESULTS: The average infection rate of influenza was (2.38 ± 0.59) × 10-10, and influenza A was (2.24 ± 0.51) × 10-10, influenza B was (2.21 ± 0.68) × 10-10. And average Re were 1.60, 1.51, 1.49. In addition, the infection rates of A /H1N1, A/H3N2, B/Yamagata and B/Victoria were (2.47 ± 0.51) × 10-10, (2.25 ± 0.48) × 10-10, (2.15 ± 0.61) × 10-10, and (2.30 ± 0.66) × 10-10 and average Re were 1.67, 1.52, 1.44, 1.56. CONCLUSION: Between each year, flu transmission capacity had fluctuation. Influenza A was more transmissible than influenza B, and during the major subtypes, influenza A/H1N1 was the most transmissible.

The impact of meteorological factors and PM2.5 on COVID-19 transmission.

In this study, we analysed the relationship between meteorological factors and the number of patients with coronavirus disease 2019 (COVID-19). The study period was from 12 April 2020 to 13 October 2020, and daily meteorological data and the daily number of patients with COVID-19 in each state of the United States were collected. Based on the number of COVID-19 patients in each state of the United States, we selected four states (California, Florida, New York, Texas) for analysis. One-way analysis of variance ( ANOVA), scatter plot analysis, correlation analysis and distributed lag nonlinear model (DLNM) analysis were used to analyse the relationship between meteorological factors and the number of patients with COVID-19. We found that the significant influencing factors of the number of COVID-19 cases differed among the four states. Specifically, the number of COVID-19 confirmed cases in California and New York was negatively correlated with AWMD (P < 0.01) and positively correlated with AQI, PM2.5 and TAVG (P < 0.01) but not significantly correlated with other factors. Florida was significantly correlated with TAVG (positive) (P < 0.01) but not significantly correlated with other factors. The number of COVID-19 cases in Texas was only significantly negatively associated with AWND (P < 0.01). The influence of temperature and PM2.5 on the spread of COVID-19 is not obvious. This study shows that when the wind speed was 2 m/s, it had a significant positive correlation with COVID-19 cases. The impact of meteorological factors on COVID-19 may be very complicated. It is necessary to further explore the relationship between meteorological factors and COVID-19. By exploring the influence of meteorological factors on COVID-19, we can help people to establish a more accurate early warning system.

Understanding counterfactuals in transparent and nontransparent context: An event-related potential investigation.

Counterfactuals describe imagined alternatives to reality that people know to be false. Successful counterfactual comprehension therefore requires people to keep in mind both an imagined hypothetical world and the presupposed real world. Counterfactual transparency, that is, the degree to which a context makes it easy to determine counterfactuality, might affect semantic processing. This might especially be the case for languages like Chinese which lack dedicated counterfactual markers and therefore are more context-dependent. Using event-related potentials, this study investigates the role of counterfactual transparency on the comprehension of Chinese counterfactuals. For transparent contexts (e.g., "If everything in the world could go back in time . . ."), in which the information needed to identify counterfactuality is highly accessible, discourse incongruent words elicited P600 effects. In contrast, for nontransparent contexts (e.g., "If better preparations were made at that time . . .") in which readers must attend to specific discourse context and engage pragmatic information to arrive at the counterfactual interpretation, discourse incongruencies gave rise to N400 effects. These findings suggest that (a) provided a constraining context, semantic processing is not disrupted by the dual nature of counterfactuality (i.e., readers can rapidly make contextually appropriate inferences to interpret subsequent narratives) and (b) the degree of transparency of the counterfactual can affect the nature of subsequent semantic processing. Our findings support the usage-based view that Chinese counterfactual comprehension is highly context-dependent and pragmatics-driven. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Literature reading modulates pronoun resolution in counterfactual world: Evidence from event-related potentials.

Counterfactuals are contrary-to-fact statements that are widely used in daily life to convey thoughts about what might have been. Different from fact-based processing, successful counterfactual comprehension requires readers to keep in mind both suppositional information and presupposed fact. Using event-related potentials, the present study investigates how the process of establishing a coreferential relation (i.e., pronoun resolution) is influenced by counterfactual context, and whether it will be modulated by individual difference in literature reading. We compared the P600 (a positive-going deflection, which often reaches its peak around 600 milliseconds after presentation of the stimulus) effects elicited by gender-mismatched pronouns in three conditionals (causal vs. hypothetical vs. counterfactual) between two groups (literature exposure high- vs. low-level group). Results show that for low-level group, incongruent pronouns elicited robust P600 effects across all three conditionals, while for high-level group, the P600 effects were pronounced only in causal and hypothetical conditionals, but not in counterfactual conditionals. These findings suggest (a) different from causal and hypothetical conditionals, the dual meaning and pragmatic implications of counterfactuals may prompt people to go beyond here and now to elaborate their mental models and entertain alternative interpretations, and (b) substantial literature exposure would further enhance pragmatic inference of counterfactual context, leading high-level readers more inclined to elaborate discourse with possible alternative inferences, while leaving low-level readers habitually resort to more straightforward coreferential interpretation. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Examining the Functional Category in Chinese-English Code-Switching: Evidence from the Eye-Movements.

To investigate the grammatical constraints of code-switching (CS hereafter) under the disputes of the constraint-based account versus the constraint-free account, the effects of functional category on CS have long been investigated in the existing studies. Thus, the present study, by asking 47 participants to take part in an eye-movement experiment, examined the potential effects of functional category on Chinese-English CS. We found that differential switch costs at varying code-switched conditions as well as robust switch effects that last from the early to the late stage. The findings could tentatively give rise to the theoretical predictions of the minimalist program, a representative of the constraint-free account rather than the functional head constraint, a typical representative of the constraint-based account. Moreover, such switch effects might initiate from the early to the very late stage in terms of time-course of CS processing.

[The analysis of event-related potentials in normal brain aging based on N-back cognitive tasks].

The purpose of this study is to investigate the change of the whole brain event-related potentials(P300) in normal brain aging based on N-back cognitive tasks. The P300 of 15 normal young people and 10 normal old people were evaluated based on N-back cognitive tasks and analyzed. The results showed that the P300 latency of old people was longer in whole brain than young people, and amplitude was increased in the frontal-central region, while significantly increased in the pre-frontal region in the same load cognitive tasks. With the cognitive task load increasing, the amplitude of old people in high-load task was higher in the whole brain than that in low-load task, mainly in in the frontal region, but the difference was not statistically significant. The latency in the high-load task was shorter in the frontal-central region of right brain than the low-load task, and the difference was statistically significant. Thus, P300 showed that the normal brain aging process is mainly reflected in the pre-frontal region, and the high-load cognitive task could better reflect the change of brain function compared with the low-load cognitive task. The finding is of revelatory meaning for diagnosis of early dementia in patients.