Global prevalence of self-harm during the COVID-19 pandemic: a systematic review and meta-analysis.

BACKGROUND: COVID-19 and its transmission mitigation measures have caused widespread mental health problems. Previous studies have suggested that psychological, economic, behavioral, and psychosocial problems associated with the COVID-19 pandemic may lead to a rise in self-harm. However, little is known about the prevalence of self-harm worldwide during COVID-19. Therefore, a quantitative synthesis is needed to reach an overall conclusion regarding the prevalence of self-harm during the pandemic. METHODS: By using permutations of COVID-19, self-harm or relevant search terms, we searched the following electronic databases from November 2019 to January 2022: Web of Science, PubMed, MEDLINE, Embase, PsycINFO, Cochrane Database of Systematic Reviews, China National Knowledge Infrastructure (CNKI), Wanfang Database and systematically reviewed the evidence according to MOOSE guidelines. We employed Cochran's chi-squared test (Cochran's Q), I2test and subgroup analysis to assess and address the heterogeneity. Sensitivity analysis was conducted by eliminating each included study individually and then combining the effects. RESULTS: Sixteen studies that met the inclusion and exclusion criteria were identified, with sample sizes ranging from 228 to 49,227. The methodological quality of the included studies was mostly at the medium level. By using a random effect model, the pooled prevalence of self-harm was 15.8% (95% CI 13.3-18.3). Based on subgroup analysis, the following characteristics of the included studies were more likely to have a higher prevalence of self-harm: studies conducted in Asia or prior to July 2020, cross-sectional studies, samples recruited in hospitals or schools, adolescents, females, the purpose of self-harm (NSSI), mental symptoms and restriction experiences. CONCLUSIONS: We provided the first meta-analytic estimated prevalence of self-harm based on a large sample from different countries and populations. The prevalence of self-harm during COVID-19 was not encouraging and requires attention and intervention. Further high-quality and prospective research are needed in order to determine the prevalence of self-harm with greater accuracy because to the clear heterogeneity across the included studies. In addition, this study also provides new directions for future research, including the identification of high-risk groups for self-harm, the formulation and implementation of prevention and intervention programs, and the long-term impact of COVID-19 on self-harm.

Corporate Tax Integrity and the Market Reactions to Covid-19: Evidence from China

We compare the market reactions to the COVID-19 crisis of Chinese listed firms with high versus low tax integrity. We show negative market reactions to the crisis across all firms, which is consistent with investors expecting COVID-19 to negatively impact firms' future prospects. Using tax-paying credit rating as a proxy for tax integrity, we find that the negative reaction to the COVID-19 crisis is significantly less for firms with high tax integrity, consistent with investors expecting tax integrity to benefit firms during the crisis. In contrast, we find no difference in the negative market reactions to the 2003 SARS outbreak for the same set of firms. As there was no tax credit rating disclosure in 2003, this serves as a control for the treatment effect. Overall, our results suggest that investors expect corporate tax integrity to mitigate the negative effect of exogenous crises such as COVID-19 on firms.

Engineering Extracellular Vesicles as Delivery Systems in Therapeutic Applications.

Extracellular vesicles (EVs) are transport vesicles secreted by living cells and released into the extracellular environment. Recent studies have shown that EVs serve as "messengers" in intercellular and inter-organismal communication, in both normal and pathological processes. EVs, as natural nanocarriers, can deliver bioactivators in therapy with their endogenous transport properties. This review article describes the engineering EVs of sources, isolation method, cargo loading, boosting approach, and adjustable targeting of EVs. Furthermore, the review summarizes the recent progress made in EV-based delivery systems applications, including cancer, cardiovascular diseases, liver, kidney, nervous system diseases, and COVID-19 and emphasizes the obstacles and challenges of EV-based therapies and possible strategies.

Do psychological distress and digital sports influence the willingness to take the vaccine and precautionary saving? Empirical evidence from Shanghai.

Aim: The COVID-19 epidemic has caused risk and uncertainty. This study answers whether and how psychological distress and digital sports influence willingness to take the vaccine and precautionary savings. Subject and methods: We conducted a cross-sectional study with an online survey sample of 1016 Shanghai residents who live and work there and are aged between 16-60. All of them experienced the COVID-19 lockdown in Shanghai. We used logistic regressions to examine the relationships between the variables of interest. Results: Three findings were demonstrated. First, psychologically distressed individuals are less inclined to take the vaccine. Second, those engaged in fitness activities via digital media platforms are more willing to get vaccinated. Third, psychologically distressed individuals and digital video-based physical exercisers are more likely to precautionary save. Conclusions: This study contributes to the literature by documenting how people changed their life from the perspective of finance and health during the lockdown and providing practical implications.

Short break drive holiday destination attractiveness during COVID-19 border closures

Research into the topic of destination image has been popular in the tourism literature since the 1970s. However, only a minority of destination image studies have focused on the context of short break drive holidays. Domestic holidays have taken on increased importance for the tourism industry in many parts of the world during travel restrictions caused by COVID-19. Building on theorizing from evolutionary psychology, this paper reports a study with the data collected from two samples in New Zealand and Australia during the COVID-19 pandemic. Conjoint analysis revealed the two most important destination attributes in terms of crowdedness and accommodation type, and latent class analysis revealed four segments. These insights have practical implications for marketers of smaller, less crowded destinations interested in the short break drive market, particularly given uncertainties about international leisure travel during the ongoing COVID-19 pandemic and the possibility of future coronavirus outbreaks. (PsycInfo Database Record (c) 2022 APA, all rights reserved)

Health belief model and social media engagement: A cross-national study of health promotion strategies against COVID-19 in 2020.

Background: Using the Health Belief Model (HBM), this study analyzed tweets related to COVID-19 published by national health departments of the United States, the South Korea, the United Kingdom, Japan, Germany, and India to explore their differences in (1) the health measures against COVID-19, (2) the health promotion strategies, (3) the social media engagements that those measures and strategies have triggered. Method: We conducted a content analysis with 1,200 randomly selected COVID-19-related tweets from six national health departments' Twitter accounts from 1 January 2020 to 31 December 2020. We coded the six HBM constructs and 21 sub-themes of the HBM constructs for each tweet. Results: Results showed that all six HBM constructs were used in the full sample. The most commonly used HBM construct was cues to action, followed by susceptibility, benefits, self-efficacy, severity, and barriers. All the HBM constructs were positively related to Twitter engagement variables except barriers. Further analysis illustrated that people from the six countries responded differently to the HBM constructs and the HBM sub-themes. Twitter users in Germany, India, the U.S., and Japan positively reacted to the clear directions of "what to do against COVID-19" (cues to action), while Twitter users in the U.S. and Japan were also eager to know the justifications for such directions (benefits); people in South Korea and the U.K. were mainly seeking a diagnosis of the severity and susceptibility of COVID-19, instead of health measures, of COVID-19 in the year 2020. Conclusions: This study showed the use of HBM constructs is generally effective in inducing Twitter engagement. The further comparison illustrated a homogenization in the promotion strategies that the health departments implemented and the health measures they promoted, yet responses to such promotions varied across nations. This study broadened the scope of HBM applications from predicting health behaviors in surveys to guiding the design of health promotion messages online.

Visual detection of SARS-CoV-2 with a CRISPR/Cas12b-based platform

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic, highlighting the unprecedented demand for rapid and portable diagnostic methods. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) proteins-based platforms have been used for the detection of pathogens. However, in further applications and research, due to multiple steps needed, many methods showed an increased risk of cross-reactivity. The thermostable Cas12b enables the combination of isothermal amplification and CRISPR-mediated detection, which could decrease the risk of cross-contamination. In this study, we developed a portable and specific diagnostic method that combined the gold nanoparticle (AuNP) with thermal stable CRISPR/Cas12b-enhanced reverse transcription loop-mediated isothermal amplification (RT-LAMP), which is called SCAN, to distinguish the N gene of SARS-CoV-2 from flu gene. We validated our method using RNA from cells transfected by plasmids. We could easily distinguish the positive results by the naked eye based on the strong molar absorption coefficient of AuNP. Moreover, SCAN has the potential for high-throughput tests owing to its convenient operation. In sum, SCAN has broken the site and equipment restrictions of traditional detection methods and could be applied outside of hospitals and clinical laboratories, greatly expanding the test of COVID-19. [Display omitted] • The CRISPR/Cas12 b was employed to realize one-tube detection. • The SCAN assay is isothermal that requires minimal equipment. • The SCAN assay has a high-throughput potential for large-scale population screening. [ FROM AUTHOR]

Relationships between urban form and air quality: A reconsideration based on evidence from China's five urban agglomerations during the COVID-19 pandemic.

The outbreak of Coronavirus disease 2019 (COVID-19) led to the widespread stagnation of urban activities, resulting in a significant reduction in industrial pollution and traffic pollution. This affected how urban form influences air quality. This study reconsiders the influence of urban form on air quality in five urban agglomerations in China during the pandemic period. The random forest algorithm was used to quantitate the urban form-air quality relationship. The urban form was described by urban size, shape, fragmentation, compactness, and sprawl. Air quality was evaluated by the Air Quality Index (AQI) and the concentration of six pollutants (CO, O3, NO2, PM2.5, PM10, SO2). The results showed that urban fragmentation is the most important factor affecting air quality and the concentration of the six pollutants. Additionally, the relationship between urban form and air quality varies in different urban agglomerations. By analyzing the extremely important indicators affecting air pollution, the urban form-air quality relationship in Beijing-Tianjin-Hebei is rather complex. In the Chengdu-Chongqing and the Pearl River Delta, urban sprawl and urban compactness are extremely important indicators for some air pollutants, respectively. Furthermore, urban shape ranks first for some air pollutants both in the Triangle of Central China and the Yangtze River Delta. Based on the robustness test, the performance of the random forest model is better than that of the multiple linear regression (MLR) model and the extreme gradient boosting (XGBoost) model.

Futile or fertile? The effect of persuasive strategies on citizen engagement in COVID-19 vaccine-related tweets across six national health departments.

National health departments across the globe have utilized persuasive strategies to promote COVID-19 vaccines through Twitter. However, the effectiveness of those strategies is unclear. This study thereby examined how national health departments deployed persuasive strategies to promote citizen engagement in COVID-19 vaccine-related tweets in six countries, including the UK, the US, Germany, Japan, South Korea, and India. Guided by the heuristic-systematic model and the health belief model, we found that national health departments differed significantly in the use of systematic-heuristic cues and health belief constructs in COVID-19 vaccine-related tweets. Generally, the provision of scientific information and appeals to anecdotes and fear positively, while appeals to bandwagon negatively, predicted citizen engagement. Messages about overcoming barriers and promoting vaccine benefits and self-efficacy positively affected engagement. Emphases of COVID-19 threats and cues to vaccinate demonstrated negative impacts. Importantly, health departments across countries often used futile or detrimental strategies in tweets. A locally adapted evidence-based approach for COVID-19 vaccination persuasion was discussed.

Time series analysis revealed prognostic value of continuous nasopharyngeal SARS-CoV-2 nucleic acid quantification for COVID-19: A retrospective study of >3000 COVID-19 patients from 2 centers.

BACKGROUND: Early stratification of disease progression remains one of the major challenges towards the post-coronavirus disease 2019 (COVID-19) era. The clinical relevance of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid load is debated due to the heterogeneity in patients' underlying health conditions. We determined the prognostic value of nasopharyngeal viral load dynamic conversion for COVID-19. METHODS: The cycling threshold (Ct) values of 28,937 nasopharyngeal SARS-CoV-2 RT-PCRs were retrospectively collected from 3,364 COVID-19 patients during hospitalization and coordinated to the onset of disease progression. The ROC curve was utilized to determine the predictive performance of the rate of Ct value alteration between two consecutive RT-PCR runs within 48 h (ΔCt%) for disease transformation across patients with different COVID-19 severity and immune backgrounds, and further validated with 1,860 SARS-CoV-2 RT-PCR results from an independent validation cohort of 262 patients. For the 67 patients with severe COVID-19, Kaplan-Meier analysis was performed to evaluate the difference in survival between patients stratified by the magnitude of Ct value alteration between the late and early stages of hospitalization. RESULTS: The kinetics of viral nucleic acid conversion diversified across COVID-19 patients with different clinical characteristics and disease severities. The ΔCt% is a clinical characteristic- and host immune status-independent indicator for COVID-19 progression prediction (AUC = 0.79, 95 % CI = 0.76 to 0.81), which outperformed the canonical blood test markers, including c-reactive protein (AUC = 0.57, 95 % CI = 0.53 to 0.61), serum amyloid A (AUC = 0.61, 95 % CI = 0.54 to 0.68), lactate dehydrogenase (AUC = 0.61, 95 % CI = 0.56 to 0.67), d-dimer (AUC = 0.56, 95 % CI = 0.46 to 0.66), and lymphocyte count (AUC = 0.62, 95 % CI = 0.58 to 0.66). Patients with persistent high SARS-CoV-2 viral load (an increase of mean Ct value < 50 %) during the first 3 days of hospitalization demonstrated a significantly unfavorable survival (HR = 0.16, 95 % CI = 0.04 to 0.65, P = 2.41 × 10-3). CONCLUSIONS: Viral nucleic acid dynamics of SARS-CoV-2 eliminates the inter-patient variance of basic health conditions and therefore, can serve as a prognostic marker for COVID-19.

Futile or fertile? The effect of persuasive strategies on citizen engagement in COVID-19 vaccine-related tweets across six national health departments

National health departments across the globe have utilized persuasive strategies to promote COVID-19 vaccines through Twitter. However, the effectiveness of those strategies is unclear. This study thereby examined how national health departments deployed persuasive strategies to promote citizen engagement in COVID-19 vaccine-related tweets in six countries, including the UK, the US, Germany, Japan, South Korea, and India. Guided by the heuristic-systematic model and the health belief model, we found that national health departments differed significantly in the use of systematic-heuristic cues and health belief constructs in COVID-19 vaccine-related tweets. Generally, the provision of scientific information and appeals to anecdotes and fear positively, while appeals to bandwagon negatively, predicted citizen engagement. Messages about overcoming barriers and promoting vaccine benefits and self-efficacy positively affected engagement. Emphases of COVID-19 threats and cues to vaccinate demonstrated negative impacts. Importantly, health departments across countries often used futile or detrimental strategies in tweets. A locally adapted evidence-based approach for COVID-19 vaccination persuasion was discussed.

Application of ultrasensitive assay for SARS-CoV-2 antigen in nasopharynx in the management of COVID-19 patients with comorbidities during the peak of 2022 Shanghai epidemics in a tertiary hospital.

OBJECTIVES: Various comorbidities associated with COVID-19 add up in severity of the disease and obviously prolonged the time for viral clearance. This study investigated a novel ultrasensitive MAGLUMI® SARS-CoV-2 Ag chemiluminescent immunoassay assay (MAG-CLIA) for diagnosis and monitoring the infectivity of COVID-19 patients with comorbid conditions during the pandemic of 2022 Shanghai. METHODS: Analytical performances of the MAG-CLIA were evaluated, including precision, limit of quantitation, linearity and specificity. Nasopharyngeal specimens from 232 hospitalized patients who were SARS-CoV-2 RT-qPCR positive and from 477 healthy donors were included. The longitudinal studies were performed by monitoring antigen concentrations alongside with RT-qPCR results in 14 COVID-19 comorbid participants for up to 22 days. The critical antigen concentration in determining virus infectivity was evaluated at the reference cycle threshold (Ct) of 35. RESULTS: COVID-19 patients were well-identified using an optimal threshold of 0.64 ng/L antigen concentration, with sensitivity and specificity of 95.7% (95% CI: 92.2-97.9%) and 98.3% (95% CI: 96.7-99.3%), respectively, while the Wondfo LFT exhibited those of 34.9% (95% CI: 28.8-41.4%) and 100% (95% CI: 99.23-100%), respectively. The sensitivity of MAG-CLIA remained 91.46% (95% CI: 83.14-95.8%) for the samples with Ct values between 35 and 40. Close dynamic consistence was observed between MAG-CLIA and viral load time series in the longitudinal studies. The critical value of 8.82 ng/L antigen showed adequate sensitivity and specificity in evaluating the infectivity of hospitalized convalescent patients with comorbidities. CONCLUSIONS: The MAG-CLIA SARS-CoV-2 Ag detection is an effective and alternative approach for rapid diagnosis and enables us to evaluate the infectivity of hospitalized convalescent patients with comorbidities.

Pharmacological Activity, Pharmacokinetics, and Clinical Research Progress of Puerarin.

As a kind of medicine and food homologous plant, kudzu root (Pueraria lobata (Willd.) Ohwi) is called an "official medicine" in Chinese folk medicine. Puerarin is the main active component extracted from kudzu root, and its structural formula is 8-ß-D-grapes pyranose-4, 7-dihydroxy isoflavone, with a white needle crystal; it is slightly soluble in water, and its aqueous solution is colorless or light yellow. Puerarin is a natural antioxidant with high health value and has a series of biological activities such as antioxidation, anti-inflammation, anti-tumor effects, immunity improvement, and cardio-cerebrovascular and nerve cell protection. In particular, for the past few years, it has also been extensively used in clinical study. This review focuses on the antioxidant activity of puerarin, the therapy of diverse types of inflammatory diseases, various new drug delivery systems of puerarin, the "structure-activity relationship" of puerarin and its derivatives, and pharmacokinetic and clinical studies, which can provide a new perspective for the puerarin-related drug research and development, clinical application, and further development and utilization.

Visual detection of SARS-CoV-2 with a CRISPR/Cas12b-based platform

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic, highlighting the unprecedented demand for rapid and portable diagnostic methods. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) proteins-based platforms have been used for the detection of pathogens. However, in further applications and research, due to multiple steps needed, many methods showed an increased risk of cross-reactivity. The thermostable Cas12 b enables the combination of isothermal amplification and CRISPR-mediated detection, which could decrease the risk of cross-contamination. In this study, we developed a portable and specific diagnostic method that combined the gold nanoparticle (AuNP) with thermal stable CRISPR/Cas12 b-enhanced reverse transcription loop-mediated isothermal amplification (RT-LAMP), which is called SCAN, to distinguish the N gene of SARS-CoV-2 from flu gene. We validated our method using RNA from cells transfected by plasmids. We could easily distinguish the positive results by the naked eye based on the strong molar absorption coefficient of AuNP. Moreover, SCAN has the potential for high-throughput tests owing to its convenient operation. In sum, SCAN has broken the site and equipment restrictions of traditional detection methods and could be applied outside of hospitals and clinical laboratories, greatly expanding the test of COVID-19.

Microfluidic bioprinting of tough hydrogel-based vascular conduits for functional blood vessels.

Three-dimensional (3D) bioprinting of vascular tissues that are mechanically and functionally comparable to their native counterparts is an unmet challenge. Here, we developed a tough double-network hydrogel (bio)ink for microfluidic (bio)printing of mono- and dual-layered hollow conduits to recreate vein- and artery-like tissues, respectively. The tough hydrogel consisted of energy-dissipative ionically cross-linked alginate and elastic enzyme-cross-linked gelatin. The 3D bioprinted venous and arterial conduits exhibited key functionalities of respective vessels including relevant mechanical properties, perfusability, barrier performance, expressions of specific markers, and susceptibility to severe acute respiratory syndrome coronavirus 2 pseudo-viral infection. Notably, the arterial conduits revealed physiological vasoconstriction and vasodilatation responses. We further explored the feasibility of these conduits for vascular anastomosis. Together, our study presents biofabrication of mechanically and functionally relevant vascular conduits, showcasing their potentials as vascular models for disease studies in vitro and as grafts for vascular surgeries in vivo, possibly serving broad biomedical applications in the future.

Effects of urban form on air quality: A case study from China comparing years with normal and reduced human activity due to the COVID-19 pandemic.

This study explored the dynamic and complex relationships between air quality and urban form when considering reduced human activities. Applying the random forest method to data from 62 prefecture-level cities in China, urban form-air quality relationships were compared between 2015 (a normal year) and 2020 (which had significantly reduced air pollution due to COVID-19 lockdowns). Significant differences were found between these two years; urban compactness, shape, and size were of prime importance to air quality in 2020, while fragmentation was the most critical factor in improving air quality in 2015. An important influence of traffic mode was also found when controlling air pollution. In general, in the pursuit of reducing air pollution across society, the best urban forms are continuous and compact with reasonable building layouts, population, and road densities, and high forest area ratios. A polycentric urban form that alleviates the negative impacts of traffic pollution is preferable. Urban development should aim to reduce air pollution, and optimizing the effects of urban form on air quality is a cost-effective way to create better living environments. This study provides a reference for decision-makers evaluating the effects of urban form on air pollution emission, dispersion, and concentration in the post-pandemic era.

Bronchodilators in Tobacco-Exposed Persons with Symptoms and Preserved Lung Function.

BACKGROUND: Many persons with a history of smoking tobacco have clinically significant respiratory symptoms despite an absence of airflow obstruction as assessed by spirometry. They are often treated with medications for chronic obstructive pulmonary disease (COPD), but supporting evidence for this treatment is lacking. METHODS: We randomly assigned persons who had a tobacco-smoking history of at least 10 pack-years, respiratory symptoms as defined by a COPD Assessment Test score of at least 10 (scores range from 0 to 40, with higher scores indicating worse symptoms), and preserved lung function on spirometry (ratio of forced expiratory volume in 1 second [FEV1] to forced vital capacity [FVC] ≥0.70 and FVC ≥70% of the predicted value after bronchodilator use) to receive either indacaterol (27.5 µg) plus glycopyrrolate (15.6 µg) or placebo twice daily for 12 weeks. The primary outcome was at least a 4-point decrease (i.e., improvement) in the St. George's Respiratory Questionnaire (SGRQ) score (scores range from 0 to 100, with higher scores indicating worse health status) after 12 weeks without treatment failure (defined as an increase in lower respiratory symptoms treated with a long-acting inhaled bronchodilator, glucocorticoid, or antibiotic agent). RESULTS: A total of 535 participants underwent randomization. In the modified intention-to-treat population (471 participants), 128 of 227 participants (56.4%) in the treatment group and 144 of 244 (59.0%) in the placebo group had at least a 4-point decrease in the SGRQ score (difference, -2.6 percentage points; 95% confidence interval [CI], -11.6 to 6.3; adjusted odds ratio, 0.91; 95% CI, 0.60 to 1.37; P = 0.65). The mean change in the percent of predicted FEV1 was 2.48 percentage points (95% CI, 1.49 to 3.47) in the treatment group and -0.09 percentage points (95% CI, -1.06 to 0.89) in the placebo group, and the mean change in the inspiratory capacity was 0.12 liters (95% CI, 0.07 to 0.18) in the treatment group and 0.02 liters (95% CI, -0.03 to 0.08) in the placebo group. Four serious adverse events occurred in the treatment group, and 11 occurred in the placebo group; none were deemed potentially related to the treatment or placebo. CONCLUSIONS: Inhaled dual bronchodilator therapy did not decrease respiratory symptoms in symptomatic, tobacco-exposed persons with preserved lung function as assessed by spirometry. (Funded by the National Heart, Lung, and Blood Institute and others; RETHINC ClinicalTrials.gov number, NCT02867761.).

Accurate quantification of SARS-CoV-2 RNA by isotope dilution mass spectrometry and providing a correction of reverse transcription efficiency in droplet digital PCR.

The novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than 505 million confirmed cases, including over 6 million deaths. Reference materials (RMs) of SARS-CoV-2 RNA played a crucial role in performance evaluation and quality control of testing laboratories. As the potential primary characterization method of RMs, reverse transcription digital PCR (RT-dPCR) measures the copy number of RNA, but the accuracy of reverse transcription (RT) efficiency has yet to be confirmed. This study established a method of enzymatic digestion followed by isotope dilution mass spectrometry (IDMS), which does not require an RT reaction, to quantify in vitro-transcribed SARS-CoV-2 RNA. RNA was digested to nucleotide monophosphate (NMP) within 15 min and analyzed by IDMS within 5 min. The consistency among the results of four different NMPs demonstrated the reliability of the proposed method. Compared to IDMS, the quantitative result of RT-dPCR turned out to be about 10% lower, possibly attributed to the incompleteness of the reverse transcription process. Therefore, the proposed approach could be valuable and reliable for quantifying RNA molecules and evaluating the RT efficiency of RT-based methods.

Evaluation of factors contributing to variability of qualitative and quantitative proficiency testing for SARS-CoV-2 nucleic acid detection.

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to unprecedented social and economic disruption. Many nucleic acid testing (NAT) laboratories in China have been established to control the epidemic better. This proficiency testing (PT) aims to evaluate the participants' performance in qualitative and quantitative SARS-CoV-2 NAT and to explore the factors that contribute to differences in detection capabilities. Two different concentrations of RNA samples (A, B) were used for quantitative PT. Pseudovirus samples D, E (different concentrations) and negative sample (F) were used for qualitative PT. 50 data sets were reported for qualitative PT, of which 74.00% were entirely correct for all samples. Forty-two laboratories participated in the quantitative PT. 37 submitted all gene results, of which only 56.76% were satisfactory. For qualitative detection, it is suggested that laboratories should strengthen personnel training, select qualified detection kits, and reduce cross-contamination to improve detection accuracy. For quantitative detection, the results of the reverse transcription digital PCR (RT-dPCR) method were more comparable and reliable than those of reverse transcription quantitative PCR (RT-qPCR). The copy number concentration of ORF1ab and N in samples A and B scattered in 85, 223, 50, and 106 folds, respectively. The differences in the quantitative result of RT-qPCR was mainly caused by the non-standard use of reference materials and the lack of personnel operating skills. Comparing the satisfaction of participants participating in both quantitative and qualitative proficiency testing, 95.65% of the laboratories with satisfactory quantitative results also judged the qualitative results correctly, while 85.71% of the laboratories with unsatisfactory quantitative results were also unsatisfied with their qualitative judgments. Therefore, the quantitative ability is the basis of qualitative judgment. Overall, participants from hospitals reported more satisfactory results than those from enterprises and universities. Therefore, surveillance, daily qualitiy control and standardized operating procedures should be strengthened to improve the capability of SARS-CoV-2 NAT.

Transmission of SARS-CoV-2 on Cold-Chain Food: Precautions Can Effectively Reduce the Risk.

The COVID-19 pandemic has generated a new era in the world, also in the food safety. Up to now, there is no evidence to suggest that people can infect COVID-19 via food contaminated by SARS-CoV-2. Here, we analyzed the results of regular SARS-CoV-2 nucleic acid testing of considerable cold-chain food practitioners, cold-chain food surfaces, and their internal or external packaging as well as their associated environments, aiming to explore the risk of cold-chain food being contaminated by SARS-CoV-2 and the probability of people infecting COVID-19 through contaminated cold-chain food in the context of COVID-19 epidemic. This study found that only two batches of cold-chain food were contaminated by SARS-CoV-2, none of the cold-chain food handler were infected due to effective regulatory measures for cold-chain food. Therefore, effective supervision and preventive methods could effectively reduce the transmission risk of SARS-CoV-2 on cold-chain food.