Should we ignore SARS-CoV-2 disease?

Current World Health Organization (WHO) reports claim a decline in COVID-19 testing and reporting of new infections. To discuss the consequences of ignoring severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, the endemic characteristics of the disease in 2023 with the ones estimated before using 2022 data sets are compared. The accumulated numbers of cases and deaths reported to the WHO by the 10 most infected countries and global figures were used to calculate the average daily numbers of cases DCC and deaths DDC per capita and case fatality rates (CFRs = DDC/DCC) for two periods in 2023. In some countries, the DDC values can be higher than the upper 2022 limit and exceed the seasonal influenza mortality. The increase in CFR in 2023 shows that SARS-CoV-2 infection is still dangerous. The numbers of COVID-19 cases and deaths per capita in 2022 and 2023 do not demonstrate downward trends with the increase in the percentages of fully vaccinated people and boosters. The reasons may be both rapid mutations of the coronavirus, which reduced the effectiveness of vaccines and led to a large number of re-infections, and inappropriate management.

Dynamics of parainfluenza virus among hospitalized children with acute respiratory tract infection under two-child policy and COVID-19 pandemic in Hubei Province, China, 2014-2022.

To analyze changes in the detection of parainfluenza virus (PIV) in children hospitalized with acute respiratory tract infection (ARTI) during 2014-2022 in Hubei Province, and explore the impact of the universal two-child policy and the public health measures against COVID-19 epidemic on the prevalence of PIV in China. The study was conducted at the Maternal and Child Health Hospital of Hubei Province. Children aged <18 years with ARTI admitted from January 2014 to June 2022 were enrolled. The infection of PIV was confirmed by the direct immunofluorescence method in nasopharyngeal specimens. Adjusted logistic regression models were used to analyze the influence of the universal two-child policy implementation and public health measurements against COVID-19 on PIV detection. Totally 75 128 inpatients meeting the criteria were enrolled in this study from January 2014 to June 2022 with an overall PIV positive rate of 5.5%. The epidemic seasons of PIV prevalence lagged substantially in 2020. A statistically significant higher positive rate of PIV was observed in 2017-2019 compared to that in 2014-2015 (6.12% vs 2.89%, risk ratio = 2.12, p < 0.001) after the implementation of the universal two-child policy in 2016. A steep decline occurred in PIV positive rate during the COVID-19 epidemic in 2020 (0.92% vs 6.92%, p < 0.001) and it rebounded during the regular epidemic prevention and control period in 2021-2022 (6.35%, p = 0.104). In Hubei Province, the implementation of the universal two-child policy might have led to an increase of PIV prevalence, and public health measures during the COVID-19 epidemic might have influenced the fluctuation in PIV detection since 2020.

The Role of Mobility in the Dynamics of the COVID-19 Epidemic in Andalusia.

Metapopulation models have been a popular tool for the study of epidemic spread over a network of highly populated nodes (cities, provinces, countries) and have been extensively used in the context of the ongoing COVID-19 pandemic. In the present work, we revisit such a model, bearing a particular case example in mind, namely that of the region of Andalusia in Spain during the period of the summer-fall of 2020 (i.e., between the first and second pandemic waves). Our aim is to consider the possibility of incorporation of mobility across the province nodes focusing on mobile-phone time-dependent data, but also discussing the comparison for our case example with a gravity model, as well as with the dynamics in the absence of mobility. Our main finding is that mobility is key toward a quantitative understanding of the emergence of the second wave of the pandemic and that the most accurate way to capture it involves dynamic (rather than static) inclusion of time-dependent mobility matrices based on cell-phone data. Alternatives bearing no mobility are unable to capture the trends revealed by the data in the context of the metapopulation model considered herein.

Short- and long-term impacts of the COVID-19 epidemic on urban PM2.5 variations: Evidence from a megacity, Chengdu.

As the new coronavirus pandemic enters its third year, its long-term impact on the urban environment cannot be ignored, especially in megacities with more than millions of people. Here, we analyzed the changes in the concentration levels, emission sources, temporal variations and holiday effects of ambient fine particulate matter (PM2.5) and its chemical components in the pre- and post-epidemic eras based on high-resolution, long time-series datasets of PM2.5 and its chemical components in Chengdu. In the post-epidemic era, the PM2.5 concentration in Chengdu decreased by 7.4%, with the components of PM2.5 decreasing to varying degrees. The positive matrix factorization (PMF) results indicated that the emissions from soil dust and industrial production were significantly lower during the COVID-19 lockdown period and post-epidemic era than those in the pre-epidemic era. In contrast, the contribution of secondary aerosols to PM2.5 during these two periods increased by 2.7% and 6.6%, respectively. Notably, we found that PM2.5 and its components substantially decreased on workdays and holidays in the post-epidemic era due to the reduced traffic volume and outdoor activities. This provides direct evidence that changes in the habitual behavior patterns of urban residents in the post-epidemic era could exert an evident positive impact on the urban environment. However, the higher PM2.5 concentration was observed due to the increased consumption of regular (As4S4, Xionghuang in Chinese) and "sulfur incense" during the Dragon Boat Festival holiday in the post-epidemic era. Finally, we examined the potential effects of sporadic COVID-19 outbreaks on the PM2.5 concentration in Chengdu, and there was no decrease in PM2.5 during two local COVID-19 outbreak events due to the strong influence of secondary pollution processes.

The importance of quarantine: modelling the COVID-19 testing process.

We incorporate the disease state and testing state into the formulation of a COVID-19 epidemic model. For this model, the basic reproduction number is identified and its dependence on model parameters related to the testing process and isolation efficacy is discussed. The relations between the basic reproduction number, the final epidemic and peak sizes, and the model parameters are further explored numerically. We find that fast test reporting does not always benefit the control of the COVID-19 epidemic if good quarantine while awaiting test results is implemented. Moreover, the final epidemic and peak sizes do not always increase along with the basic reproduction number. Under some circumstances, lowering the basic reproduction number increases the final epidemic and peak sizes. Our findings suggest that properly implementing isolation for individuals who are waiting for their testing results would lower the basic reproduction number as well as the final epidemic and peak sizes.

Psychological distress and academic self-efficacy of nursing undergraduates under the normalization of COVID-19: multiple mediating roles of social support and mindfulness.

BACKGROUND: Nursing undergraduates' academic self-efficacy is a significant factor in determining their learning motivation, cognition, and emotions. It has a significant impact on improving academic performance and achieving learning goals. METHODS: To explore the mechanism of psychological distress affecting the academic self-efficacy of nursing undergraduates, the generalized anxiety disorder scale-7, patient health questionnaire-9, academic self-efficacy scale, perceived social support scale and mindful attention awareness scale were conducted. RESULTS: Model fitness indexes of the structural equation model is good (CMIN/DF = 1.404, RMSEA = 0.042, GFI = 0.977, IFI = 0.977, TLI = 0.954, CFI = 0.975, NFI = 0.923). Structural equation model analysis showed that social support and mindfulness were the mediating variables of psychological distress on academic self-efficacy. Mediating variables accounted for 44% of the total effect value (- 0.3) with a value of - 0.132. Three paths were verified: psychological distress indirectly affected academic self-efficacy through social support (- 0.064); psychological distress indirectly affected academic self-efficacy through mindfulness (- 0.053); psychological distress indirectly affected academic self-efficacy through social support and mindfulness (- 0.015). CONCLUSIONS: Social support and mindfulness play significant mediating roles in the effect of psychological distress on academic self-efficacy, and the chain mediating role of social support and mindfulness is also significant. Educators may mitigate the impact of psychological distress on academic self-efficacy by enhancing students' social support and mindfulness.

Anxiety as a mediator in the relationship between the socioeconomic impact of COVID-19 and quality of life: a cross-sectional study in Vietnam.

Previous studies have investigated the effects of the pandemic on quality of life; both economical and psychosocial effects were explored. Some studies also mentioned mediating factors as mechanisms in this relationship; however, the mediating role of anxiety has not been examined. The present study examined the mediating effects of anxiety on the relationship between socioeconomic impact of COVID-19 and quality of life. An online survey of 280 Vietnamese residents was conducted in the context of the pandemic outbreak. Anxiety was found to be a completely mediating variable in the association between the socioeconomic impact of the pandemic and quality of life during the lockdown period. This finding contributes to a better understanding of how the pandemic affects people's quality of life and serves as the foundation for lessening the negative effects of the epidemic on people's lives.

Gone with the epidemic? The spatial effects of the Covid-19 on global investment network.

The outbreak of Covid-19 epidemic has a prolonged impact on global economic activities. In recent years, many scholars have been motivated to estimate the effects of Covid-19 shock on global foreign direct investment (FDI). However, existing studies have not paid enough attention to the spillover effects caused by the epidemic. Although few academic works have explored the geographic-neighboring spillover effects of epidemic shock on global investment, we further extent the understanding of the spillover effects in an economic network. On the basis of country-month greenfield FDI panels, we construct a spatial Durbin model, and figure out that Covid-19 shock may have positive FDI spillover effects in an economic network via global FDI transfers. Furthermore, we find that such spillovers are greatly conditioned by country-level network position and institutional ties among nations. Our research suggests that global FDI transfers may partly offset economic-adverse effects of the Covid-19 shock. While global countries, especially those in the Global South, should be more closely embedded in the global investment network in such an uncertain environment.

Supply chain planning of vaccine and pharmaceutical clusters under uncertainty: The case of COVID-19.

As an abrupt epidemic occurs, healthcare systems are shocked by the surge in the number of susceptible patients' demands, and decision-makers mostly rely on their frame of reference for urgent decision-making. Many reports have declared the COVID-19 impediments to trading and global economic growth. This study aims to provide a mathematical model to support pharmaceutical supply chain planning during the COVID-19 epidemic. Additionally, it aims to offer new insights into hospital supply chain problems by unifying cold and non-cold chains and considering a wide range of pharmaceuticals and vaccines. This approach is unprecedented and includes an analysis of various pharmaceutical features such as temperature, shelf life, priority, and clustering. To propose a model for planning the pharmaceutical supply chains, a mixed-integer linear programming (MILP) model is used for a four-echelon supply chain design. This model aims to minimize the costs involved in the pharmaceutical supply chain by maintaining an acceptable service level. Also, this paper considers uncertainty as an intrinsic part of the problem and addresses it through the wait-and-see method. Furthermore, an unexplored unsupervised learning method in the realm of supply chain planning has been used to cluster the pharmaceuticals and the vaccines and its merits and drawbacks are proposed. A case of Tehran hospitals with real data has been used to show the model's capabilities, as well. Based on the obtained results, the proposed approach is able to reach the optimum service level in the COVID conditions while maintaining a reduced cost. The experiment illustrates that the hospitals' adjacency and emergency orders alleviated the service level significantly. The proposed MILP model has proven to be efficient in providing a practical intuition for decision-makers. The clustering technique reduced the size of the problem and the time required to solve the model considerably.

Refining index to measure physical activity inequality: which group of the population is the most vulnerable?

BACKGROUND: The existing body of research mostly discusses inequality in physical activity (PA) based on the difference in the level of moderate-to-vigorous physical activity (MVPA). Evidence is lacking on the quantified inequality measures (e.g., how big the inequality is, and the distribution) in order to identify the most vulnerable groups of a population. This study measured PA inequality among Thai adults by using three parameters to construct an inequality index: (1) Proportion of the population with sufficient MVPA; (2) Cumulative minutes of MVPA; and (3) The Gini coefficient. METHODS: This study employed three rounds of data from Thailand's Surveillance on Physical Activity (SPA) 2019-2021. In each round, over 6,000 individuals age 18-64 years were selected as nationally-representative samples, and were included in the analysis. PA inequality was constructed by using three parameters, with a combination of the three as the final measure, to identify the sub-groups of the Thai adults who are most vulnerable: groups with the least MVPA, highest insufficiency, and highest inequality index (Gini). RESULTS: Covid-19 containment measures have widened the gap in PA inequality, as shown by a declining proportion of the population meeting the recommended guidelines, from 74.3% in 2019 to 56.7% in 2020 and 65.5% in 2021. PA inequality existed in all sub-populations. However, by combining three parameters, the most vulnerable groups during the Covid-19 epidemic were identified as follows: (1) Those with no income; (2) The unemployed; (3) Those who have no access to PA facilities; (4) Older adults aged 60 + years; and (5) Those earning < 3,500 baht per month. Further, residents of Bangkok, young adults aged 18-24, individuals who attained primary level education or less, those who had no exposure to a PA awareness campaign and those who have a debilitating chronic disease also had elevated risk of PA insufficiency. CONCLUSION: A concerning level of PA inequality existed in all sub-populations. The use of combined indicators in measuring PA inequality should aid in determining the most vulnerable groups of the population with a refined procedure. This method can be applied in many settings since the baseline data used to measure inequality (i.e., percent sufficient and cumulative minutes of MVPA) are widely available.

Influence of COVID-19 lockdown on the variation of organic aerosols: Insight into its molecular composition and oxidative potential.

To prevent the transmission of the novel coronavirus disease 2019 (COVID-19), China adopted nationwide lockdown measures on January 25, 2020, leading to an evident diminution in the observed air pollutants. To investigate the influence of the lockdown on atmospheric chemistry, the specific molecular composition, oxidative potential of organic aerosols (OAs) in PM2.5 were studied using a high-resolution orbitrap mass spectrometry at a typical coal-combustion city, Linfen, in the North China Plain (NCP). The major air pollutants including PM2.5, PM10, SO2, NO2, and CO were observed to be diminished by 28.6-45.4%, while O3 was augmented by 52.5% during the lockdown compared to those before the lockdown. A significant decrease of oxygen-containing (CHO) compounds (24.7%) associated with anthropogenic acids was observed during the lockdown, implying a reduction in fossil fuel combustion. The coal-burning related sulfur-containing organosulfates (CHOS-) and nitrooxy-sulfates (CHONS-) have also shown attenuated in both their relative abundances and anthropogenic/biogenic ratios. Amine/amide-like CHON + components have decreased by 27.6%, while nitro/nitrooxy-containing CHON- compounds have only decreased by 7.1%. Multi-source nitrogen-containing (CHN) compounds have shown a moderate elimination of 24.0%, while the identified high-condensed azaarenes have fallen from 17.7% to 14.7%, implying a potential reduction in the health risk of OAs during quarantine. The measurement of OAs' oxidative potential through dithiothreitol (DTT) assay has confirmed that as it had dropped from 0.88 nmol min-1 m-3 to 0.80 nmol min-1 m-3. High correlations were observed between the abundance of OA subgroups with the concentration of PM2.5 after the execution of the lockdown, suggesting a potential elevation in the contribution of organic components to the total PM2.5 level. Our study provides insightful compositional and health-related information in the variation of OAs during the lockdown period and attests to the validity of joint-control strategy in controlling the level and health risks of numerous atmospheric pollutants.

Effects of tree canopy on psychological distress: A repeated cross-sectional study before and during the COVID-19 epidemic.

BACKGROUND: During the COVID-19 epidemic period, people showed a stronger connection to the environment within their communities. Although tree canopy in residential areas has been shown to positively affect psychological distress, it is not clear whether the COVID-19 epidemic played a role in this process. Elucidation of the relationship between tree canopy and the impact on psychological distress during the COVID-19 epidemic could provide valuable information as to the best methods to help individuals cope with urban mental stress events. METHODS: A total of 15 randomly selected residential areas of Beijing were enrolled in this repeated cross-sectional study. A total of 900 residents were included in the two-waves of the investigation (450 residents per wave) before and during the COVID-19 epidemic (i.e., May 2019 and May 2020). Psychological distress was estimated using the 12-question General Health Questionnaire (GHQ-12). Tree canopy coverage (TCC) was measured through visual interpretation based on the 2013 data sources (World View 2 satellite imagery of Beijing urban areas with a resolution of 0.5 m). The demographic characteristics, distance to the nearest surrounding green or blue space, residential area house price, household density, and construction year were also collected in this study. A multivariate logistic regression, relative risk due to interaction (RERI), and synergy index (SI) were used to explore the relationships among tree canopy, COVID-19, and psychological distress. RESULTS: The negative impact of the COVID-19 epidemic on mental health was significant, with the prevalence of psychological distress increased 7.84 times (aOR = 7.84, 95% CI = 4.67-13.95) during the COVID-19 epidemic period. Tree canopy coverage in the group without psychological distress was significantly higher than that of the psychologically distressed group (31.07 ± 11.38% vs. 27.87 ± 12.97%, P = 0.005). An increase in 1% of TCC, was related to a 5% decrease in the prevalence of psychological distress (aOR = 0.95, 95% CI = 0.93-0.98). An antagonism joint action between tree canopy and the COVID-19 epidemic existed (RERI = 1.09, 95% CI = 0.72-1.47; SI = 0.16, 95% CI = 0.05-0.52), and persisted enhancing only in medium (26.45%-33.21%) and above TCC level. Correlation of GHQ items and TCC significantly differed between the COVID-19 non-epidemic and epidemic periods, with the effects of tree canopy on GHQ-12 items covering topics, such as social function and depression, presumably absent because of epidemic limitations. CONCLUSIONS: This study indicates that the COVID-19 epidemic harmed mental health and verified the positive effects of residential tree canopy on psychological distress in Beijing. We suggest paying more attention to residents in areas of low TCC and dealing with psychological distress caused by public health stress events based on tree canopy strategies.

Controlling Multiple COVID-19 Epidemic Waves: An Insight from a Multi-scale Model Linking the Behaviour Change Dynamics to the Disease Transmission Dynamics.

COVID-19 epidemics exhibited multiple waves regionally and globally since 2020. It is important to understand the insight and underlying mechanisms of the multiple waves of COVID-19 epidemics in order to design more efficient non-pharmaceutical interventions (NPIs) and vaccination strategies to prevent future waves. We propose a multi-scale model by linking the behaviour change dynamics to the disease transmission dynamics to investigate the effect of behaviour dynamics on COVID-19 epidemics using game theory. The proposed multi-scale models are calibrated and key parameters related to disease transmission dynamics and behavioural dynamics with/without vaccination are estimated based on COVID-19 epidemic data (daily reported cases and cumulative deaths) and vaccination data. Our modeling results demonstrate that the feedback loop between behaviour changes and COVID-19 transmission dynamics plays an essential role in inducing multiple epidemic waves. We find that the long period of high-prevalence or persistent deterioration of COVID-19 epidemics could drive almost all of the population to change their behaviours and maintain the altered behaviours. However, the effect of behaviour changes fades out gradually along the progress of epidemics. This suggests that it is essential to have not only persistent, but also effective behaviour changes in order to avoid subsequent epidemic waves. In addition, our model also suggests the importance to maintain the effective altered behaviours during the initial stage of vaccination, and to counteract relaxation of NPIs, it requires quick and massive vaccination to avoid future epidemic waves.

Research Note: Gender Differences in Employment During the COVID-19 Epidemic.

We investigate the impact of the COVID-19 epidemic on gender disparities in three employment outcomes: labor force participation, full-time employment, and unemployment. Using data from the monthly Current Population Survey, in this research note we test individual fixed-effects models to examine the employment status of women relative to that of men in the nine months following the onset of the epidemic in March of 2020. We also test separate models to examine differences between women and men based on the presence of young children. Because the economic effects of the epidemic coincided with the summer months, when women's employment often declines, we account for seasonality in women's employment status. After doing so, we find that women's full-time employment did not decline significantly relative to that of men during the months following the beginning of the epidemic. Gender gaps in unemployment and labor force participation did increase, however, in the early and later months of the year, respectively. Our findings regarding women's labor force participation and employment have implications for our understanding of the long-term effects of the health crisis on other demographic outcomes.

Public engagement in decision-making regarding the management of the COVID-19 epidemic: Views and expectations of the 'publics'.

BACKGROUND: In the management of epidemics, like COVID-19, trade-offs have to be made between reducing mortality and morbidity and minimizing socioeconomic and political consequences. Traditionally, epidemic management (EM) has been guided and executed attentively by experts and policymakers. It can, however, still be controversial in the public sphere. In the last decades, public engagement (PE) has been successfully applied in various aspects of healthcare. This leads to the question if PE could be implemented in EM decision-making. METHODS: From June to October 2020, seven deliberative discussion focus groups were executed with 35 Dutch citizens between 19 and 84 years old. Their views on PE in COVID-19 management were explored. The deliberative approach allows for the education of participants on the topic before the discussion. The benefits, barriers, timing and possible forms of PE in EM were discussed. RESULTS: Almost all participants supported PE in EM, as they thought that integrating their experiences and ideas would benefit the quality of EM, and increase awareness and acceptance of measures. A fitting mode for PE was consultation, as it was deemed important to provide the public with possibilities to share ideas and feedback; however, final authority remained with experts. The publics could particularly provide input about communication campaigns and control measures. PE could be executed after the first acute phase of the epidemic and during evaluations. CONCLUSIONS: This paper describes the construction of an empirically informed framework about the values and conditions for PE in EM from the perspective of the public. Participants expressed support to engage certain population groups and considered it valuable for the quality and effectiveness of EM; however, they expressed doubts about the feasibility of PE and the capabilities of citizens. In future studies, these results should be confirmed by a broader audience. PATIENT OR PUBLIC CONTRIBUTION: No patients or members of the public were involved in the construction and execution of this study. This study was very exploratory, to gain a first insight into the views of the public in the Netherlands, and will be used to develop engagement practices accordingly. At this stage, the involvement of the public was not yet appropriate.

Temporal changes in health-related lifestyle during the COVID-19 epidemic in Finland - a series of cross-sectional surveys.

BACKGROUND: Public health recommendations and governmental restrictions during the COVID-19 epidemic have affect everyday life. This study aimed to examine temporal changes in health-related lifestyle and the accumulation of positive and negative changes in the key lifestyle factors (vegetable consumption, leisure-time physical activity, sleeping, alcohol consumption, smoking) in the same individuals among Finnish adults during the epidemic. METHODS: This study was based on a series of cross-sectional surveys conducted between April 2020 and June 2021 to investigate antibody levels for the new coronavirus in the population. In each survey, a random sample of adults (18 to 69 years) from five university hospital regions were invited. A total of 5655 (response rate 32%) responded to the questionnaire including questions on lifestyle changes during epidemic. RESULTS: On average one-sixth of respondents (17%) reported at least two negative changes in the key lifestyle factors during the study period. An increase in snacking and sleep problems and decrease in leisure-time physical activity and active commuting to work were the most common of individual negative changes. The proportion of negative changes in physical activity increased as the epidemic drags on. In contrast, on average every seventh of the respondents (14%) reported at least two positive lifestyle changes in the key lifestyle factors. The most common individual positive changes were increased consumption of fruit, berries and vegetables and decreased consumption of alcohol. More negative changes were reported on average, when both negative and positive changes in the key lifestyle factors were summed. The most negative changes were reported in the late 2020. CONCLUSION: The results of the present study suggest that the lifestyle changes during the COVID-19 epidemic have been diverse being on average more commonly unfavorable than favorable for health. The deteriorated epidemic situation in the late 2020 and, on the other hand, prolonged epidemic predisposed to negative lifestyle changes. Further studies are important to examine whether these changes are maintained over time and to identify the factors that contribute to changes and their accumulation in the same individuals. Health promotion actions are needed to prevent the long-term effects of the epidemic on health and welfare.

The influence of COVID-19 epidemic on BDI volatility: An evidence from GARCH-MIDAS model.

In this study, we use the sample data from Jan 22, 2020 to Jan 21, 2022 to investigate the impacts of added infection number on the volatility of BDI. Under this structure, the control variables (freight rate, Brent crude oil price, container idle rate, port congestion level, global port calls) are added to test whether the information contained in the added infection number is covered. In the GARCH-MIDAS model, we divide the volatility of BDI into the long-term and short-term components, then employ in the least squares regression to empirically test the influences of added infection number on the volatility. From the analysis, we find the added infection numbers effectively impact the BDI volatility. In addition, whether the freight rate, Brent crude oil price, container idle rate, port congestion level, global port calls and other variables are considered alone or at the same time, further the added infection number still significantly influences the volatility of BDI. By studying the ability of the confirmed number to explain the volatility of BDI, a new insight is provided for the trend prediction of BDI that the shipping industry can take the epidemic development of various countries as a reference to achieve the purpose of cost or risk control.

Assessing the "negative effect" and "positive effect" of COVID-19 in China.

The COVID-19 pandemic lockdowns led to a sharp drop in socio-economic activities in China in 2020, including reductions in fossil fuel use, industry productions, and traffic volumes. China's economy suffered a serious negative effect from COVID-19. However, there is a "positive effect" on CO2 emissions reduction. Here, for the first time, this paper constructs a new model named "Weighted Multi-regional Hypothetical Extraction Method (WMHEM)" based on a multiregional input-output model. It not only solves the problems of traditional HEM methods such as improper use of assumptions, excessive reliance on industry intermediate input, but also accurately reflects the impact of external shocks on the inter-industry linkages. By using the monthly economic data of each provinces in China during COVID-19 (except Hong Kong，Macao and Taiwan) an the latest Multi-regional input-output tables, the "economic negative effect" and "CO2 emission positive effect" under COVID-19 in China are measured. Results show that COVID-19 lockdown was estimated to have reduced China's CO2 emissions substantially between January and March in 2020, with the largest reductions in February. With the spread of coronavirus controlled, China's CO2 emissions rebounded in April. In addition, key emission reduction sectors and key development encouraged sectors are selected by combining "economic negative effect" and "CO2 emission positive effect" during COVID-19. Therefore, policies recommendations are put forward based on forward and backward linkages respectively which are from two ends of the supply chain to turn pandemic-related CO2 emissions declines into firm climate action.

Assessment of health benefit of PM2.5 reduction during COVID-19 lockdown in China and separating contributions from anthropogenic emissions and meteorology.

The national lockdown policies have drastically disrupted socioeconomic activities during the COVID-19 pandemic in China, which provides a unique opportunity to investigate the air quality response to such anthropogenic disruptions. And it is meaningful to evaluate the potential health impacts of air quality changes during the lockdown, especially for PM2.5 with adverse health effects. In this study, by using PM2.5 observations from 1388 monitoring stations nationwide in China, we examine the PM2.5 variations between the COVID-19 lockdown (February and March in 2020) and the same period in 2015-2019, and find that the national average of PM2.5 decreases by 18 µg/m3, and mean PM2.5 for most sites (about 75%) decrease by 30%-60%. The anthropogenic and meteorological contributions to these PM2.5 variations are also determined by using a stepwise multiple linear regression (MLR) model combined with the Kolmogorov-Zurbenko filter. Our results show that the change of anthropogenic emissions is a leading contributor to those widespread PM2.5 reductions, and meteorological conditions have the negative influence on PM2.5 reductions for some regions, such as Beijing-Tianjin-Hebei (BTH). Additionally, the avoided premature death due to PM2.5 reduction is estimated as a predicted number based on a log-linear concentration-response function. The total avoided premature death is 9952 in China, with dominant contribution (94%) from anthropogenic emission changes. For BTH, Yangtze River Delta, Pearl River Delta and Hubei regions, the reductions of PM2.5 are 24.1, 24.3, 13.5 and 29.5 µg/m3, with the avoided premature deaths of 1066, 1963, 454 and 583, respectively.

Stability analysis of COVID-19 model with fractional-order derivative and a delay in implementing the quarantine strategy.

This study presents methods of hygiene and the use of masks to control the disease. The zero basic reproduction number can be achieved by taking the necessary precautionary measures that prevent the transmission of infection, especially from uninfected virus carriers. The existence of time delay in implementing the quarantine strategy and the threshold values of the time delay that keeping the stability of the system are established. Also, it is found that keeping the infected people quarantined immediately is very important in combating and controlling the spread of the disease. Also, for special cases of the system parameters, the time delay can not affect the asymptotic behavior of the disease. Finally, numerical simulations have been illustrated to validate the theoretical analysis of the proposed model.