A local COVID - 19 outbreak in Dalian caused by imported cold - chain products contaminated by SARS-CoV-2

On December 15, 2020, four dock workers tested positive for severe acute respiratory syndrome-coronavirus 2 (SARS-COV-2) nucleic acids and were reported by Dalian. Up until then, Dalian City had not reported local cases for 136 consecutive days. In this coronavirus disease 2019 (COVID-19) outbreak (referred to as the "Dalian COVID-19 outbreak"), samples from all infected persons (83) and part from the ship cargoes in contact With them during December 15, 2020 to January 8, 2021 were collected. Confirmed cases accounted for 61.45% (51/83) and asymptomatic infections accounted for 38.55% (32/83). Through high-throughput sequencing, 76 SARS-CoV-2 whole-genome sequences were obtained, of which 72 (86.75%) were from clinical samples, and 4 from cold-chain food packaging surface samples on cargo ship A of country R. Refer to Wuhan reference strain (NC_045512), genome analysis revealed 12-16 nucleotide mutations in 76 whole genomes sharing 12 nucleotide mutations and belong to the SARS-CoV-2 branch of B.1.1. Viral genomics and field epidemiological investigations showed that the Dalian COVID-19 outbreak was a local epidemic caused by dock workers infected with imported cold - chain products contaminated with SARS - CoV - 2. During transmission, 3 Virus generations and three relatively independent transmission chains were formed.

Gender-Specific Related Factors for Suicidal Ideation During COVID-19 Pandemic Lockdown Among 5,175 Chinese Adolescents

Background Suicide was an urgent issue during the pandemic period in adolescents. However, few studies were focused on suicide during the coronavirus disease 2019 (COVID-19) pandemic lockdown. Methods An online survey was conducted among 5,175 Chinese adolescents from June 9th to 29th in 2020 to investigate the prevalence of suicidal ideation (SI) during COVID-19 pandemic lockdown. A gender-specific stepwise logistic regression model was used. All analyses were performed with STATA 15.0. Results About 3% of the participants had reported having SI during the COVID-19 pandemic lockdown period. The prevalence of female SI (3.64%, 95% CI: 2.97–4.45%) was higher than that of males (2.39%, 95% CI: 1.88–3.05%) (χ2 = 6.87, p = 0.009). Quarreling with parents [odds ratio (OR) = 9.73, 95% CI: 5.38–17.59], insomnia (OR = 5.28, 95% CI: 2.81–9.93), previous suicide attempt history (OR = 3.68, 95% CI: 1.69–8.03), previous SI history (OR = 2.81, 95% CI: 1.30–6.06), and feeling depressed during pandemic lockdown (OR = 2.26, 95% CI: 1.22–4.18) were positively associated with the males' SI. However, having emptiness inside (OR = 4.39, 95% CI: 2.19–8.79), quarreling with parents (OR = 3.72, 95% CI: 2.16–6.41), insomnia (OR = 3.28, 95% CI: 1.85–5.80), feeling anxious (OR = 2.62, 95% CI: 1.46–4.70), and longing for father's emotional warmth (OR = 0.38, 0.20–0.72) were associated mostly with females' SI. Conclusions Female adolescents, who felt emptiness from their families and their fathers' emotional warmth, were at much higher risk of having SI during COVID-19 lockdown. We must specify a suicide prevention policy and interventions for adolescents in the pandemic crisis based on gender gaps.

The impact of self-efficacy on first onset and prognosis of major depressive disorder: findings from a longitudinal study in a sample of Chinese first-year university students.

BACKGROUND: Self-efficacy is a pivotal factor in the etiology and prognosis of major depression. However, longitudinal studies on the relationship between self-efficacy and major depressive disorder (MDD) are scarce. The objectives were to investigate: (1) the associations between self-efficacy and the 1-year and 2-year risks of first onset of MDD and (2) the associations between self-efficacy and the 1-year and 2-year risks of the persistence/recurrence of MDD, in a sample of first-year university students. METHODS: We followed 8079 first-year university students for 2 years from April 2018 to October 2020. MDD was ascertained by the Chinese version of the Composite International Diagnostic Interview (CIDI-3.0) based on self-report. Self-efficacy was measured by the 10-item General Self-efficacy (GSE) scale. Random effect logistic regression modeling was used to estimate the associations. RESULTS: Among participants without a lifetime MDD, the data showed that participants with high baseline GSE scores were associated with a higher risk of first onset of MDD over 2 years [odds ratio (OR) 1.04, 95% confidence interval (CI) 1.01-1.08]. Among those with a lifetime MDD, participants with high baseline GSE scores were less likely to have had a MDD over 2 years (OR 0.93, 95% CI 0.88-0.99) compared to others. CONCLUSIONS: A high level of GSE may be protective of the risk of persistent or recurrent MDD. More longitudinal studies in university students are needed to further investigate the impact of GSE on the first onset of MDD.

Lung Ultrasound in COVID-19 Patients: Characteristics and Factors Affecting its Diagnostic Accuracy (preprint)

Background: Although chest computed tomography (CT) is the gold standard for diagnosing the majority of lung conditions, its use in screening patients for coronavirus disease 2019(COVID-19) pneumonia is not recommended. Lung ultrasound (LUS) is an alternative modality. To investigate the characteristics and diagnostic accuracy (DA) of bedside ultrasound for lung lesions in patients with COVID-19 and to determine the factors influencing the DA of lung ultrasound (LUS). Methods: A total of 330 patients with COVID-19 admitted to the hospital between February and March 2020 were retrospectively recruited. The imaging characteristics of LUS and computed tomography (CT) scans were analysed and summarized. DA was calculated using a chest CT scan as the reference standard. Furthermore, a binary logistic regression analysis was conducted to investigate the factors influencing the DA of LUS for interstitial syndrome. Results: The ultrasound findings of COVID-19 patients presented mainly as B lines (195/330, 59.1%), unsmooth or interrupted pleural lines (118/330, 35.8%), consolidation lesions (74/330, 22.4%), and pleural effusion (11/330, 3.33%). Compared with the chest CT scan, the DA of LUS for interstitial syndrome, consolidation, pleural effusion, and pleural thickening were 0.821, 0.927, 0.988, and 0.863, respectively. The diagnostic coincidence rate of LUS and chest CT in the mild, common, severe, and critical groups were 93%, 68.6%, 100%, and 100%, respectively. According to the results of the binary logistic regression, sex, disease duration, experience of the doctor, and involved lobes were independent predictors of the DA for interstitial syndrome. Conclusions: LUS had good diagnostic performance for diagnosing COVID-19 pneumonia, and showed a relatively low DA for interstitial syndrome. Female sex, doctors with less experience, long disease duration, and lesions limited to the upper or lower lobes may decrease the DA.

Research on the influence of college students’ self-directed learning behavior based on online learning platform

COVID-19 has made physical education almost forced to move to online, and the main way to acquire knowledge has also been transformed from offline to online. Especially for college students, as a group of external conditions supporting and having a strong sense of autonomy, online learning habits will have a lasting impact on subsequent learning production, and even become the second important knowledge acquisition way besides classroom. Therefore, it is necessary to study the use of online learning platform and self-directed learning behavior of college students. Based on TAM and UTAUT, this study supplements the perception theory and self-directed learning theory by extracting the influence factors of live platform. Based on the data analysis of smartpls and SPSS, this paper constructs the structural equation model of self-learning behavior of College Students’ online learning platform, explores the external and internal influence mechanism of self-learning behavior, and provides guidance for online learning platform practitioners and college students’ self-learning behavior.

Associations between feelings/behaviors during COVID-19 pandemic lockdown and depression/anxiety after lockdown in a sample of Chinese children and adolescents.

BACKGROUND: Children and adolescents may be more susceptible to mental disorders due to COVID-19 pandemic than adults. This study aimed to identify correlated factors for depression/anxiety among children and adolescents after COVID-19 pandemic lockdown. METHODS: An online survey by cluster sampling was conducted after lockdown in 5175 Chinese children and adolescents with informed consents from their parents. The 9-item Patient Health Questionnaire and the 7-item Generalized Anxiety Disorder scales with 10-point cutoff were used to measure depression and anxiety, separately. Stepwise logistic regression was conducted. Stata 15.1 Version was used. RESULTS: 12.33% and 6.26% of all participants reported depression and anxiety after lockdown, separately. Suicidal ideation, quarreling with parents, insomnia, difficulty in concentrating during online learning, and anxious and depressed mood during lockdown were positively associated with depression and anxiety after lockdown. Missing teachers was negatively associated with both depression and anxiety. Living in urban and not living with parents were positively associated with depression. LIMITATIONS: The past history and familial history of mental disorders have not been collected. The recall biases for collecting self-reporting information might exist, and the causal inferences cannot be drawn. CONCLUSIONS: The prevalence of depression and anxiety in children and adolescents might decline a bit after lockdown but is still at a high level after lockdown. Gatekeepers should pay more attention to modifiable factors of psychological well-being in children and adolescents, including family and school contexts and even feelings and behaviors during COVID-19 pandemic lockdown.

Analysis on the Characteristics of Air Pollution in China during the COVID-19 Outbreak

The COVID-19 pandemic poses a serious global threat to human health. In China, the government immediately implemented lockdown measures to curb the spread of this virus. These measures severely affected transportation and industrial production across the country, resulting in a significant change in the concentration of air pollutants. In this study, the Euclidean distance method was used to select the most similar meteorological field during the COVID-19 lockdown period. Changes in the concentration of air pollutants in China were analyzed under similar meteorological background conditions. Results indicate that, compared with data from 2015–2019, air quality in China significantly improved;with the exception of ozone (O3), the concentration of major air pollutants declined. Compared with baseline conditions, the reduction of air pollutants in China from 25 January to 22 February 2020 (Period 2) was the most significant. In particular, NO2 decreased by 41.7% in the Yangtze River Delta. In Period 2, the reduction of air pollutants in areas other than Hubei gradually decreased, but the reduction of NO2 in Wuhan reached 61.92%, and the reduction of air pollutants in various regions after February 23 was significantly reduced. By excluding the influence of meteorological factors and calculating the contribution of human activities to atmospheric pollutants by linear fitting, in Period 2 the effect of artificial controls on NO2 in Wuhan attained 30.66%, and reached 48.17% from 23 February to 23 March (Period 3). Results from this investigation provides effective theoretical support for pollution prevention and control in China.

Self-Interest Bias in the COVID-19 Pandemic: A Cross-Cultural Comparison between the United States and China (preprint)

In the global crisis of the COVID-19 pandemic, many countries attempt to enforce new social norms to prevent the further spread of the coronavirus. A key to the success of these measures is the individual adherence to norms that are collectively beneficial to contain the spread of the pandemic. However, individuals’ self-interest bias (i.e., the prevalent tendency to license own but not others’ self-serving acts or norm violations) can pose a challenge to the success of such measures. The current research examines COVID-19-related self-interest bias from a cross-cultural perspective. Two studies (N = 1,558) sampled from the United States and China consistently revealed that participants from the United States evaluated their own self-serving acts (exploiting test kits in Study 1; social gathering and sneezing without covering the mouth in public in Study 2) as more acceptable than identical deeds of others, while such self-interest bias did not emerge among Chinese participants. Cultural underpinnings of independent versus interdependent self-construal may influence the extent to which individuals apply self-interest bias to justifications of their own self-serving behaviors during the pandemic.

Dynamic change process of target genes by RT-PCR testing of SARS-Cov-2 during the course of a Coronavirus Disease 2019 patient.

We report the dynamic change process of target genes by RT-PCR testing of SARS-Cov-2 during the course of a COVID-19 patient: from successive negative results to successive single positive nucleocapsid gene, to two positive target genes (orf1ab and nucleocapsid) by RT-PCR testing of SARS-Cov-2, and describe the diagnosis, clinical course, and management of the case. In this case, negative results of RT-PCR testing was not excluded to diagnose a suspected COVID-19 patient, clinical signs and symptoms, other laboratory findings, and chest CT images should be taken into account for the absence of enough positive evidence. This case highlights the importance of successive sampling and testing SARS-Cov-2 by RT-PCR as well as the increased value of single positive target gene from pending to positive in two specimens to diagnose laboratory-confirmed COVID-19.