Active Enrichment of Nanoparticles for Ultra-Trace Point-of-Care COVID-19 Detection.

Active enrichment can detect nucleic acid at ultra-low concentrations without relatively time-consuming polymerase chain reaction (PCR), which is an important development direction for future rapid nucleic acid detection. Here, we reported an integrated active enrichment platform for direct hand-held detection of nucleic acid of COVID-19 in nanoliter samples without PCR. The platform consists of a capillary-assisted liquid-carrying system for sampling, integrated circuit system for ultrasound output, and cell-phone-based surface-enhanced Raman scattering (SERS) system. Considering the acoustic responsiveness and SERS-enhanced performance, gold nanorods were selected for biomedical applications. Functionalized gold nanorods can effectively capture and enrich biomarkers under ultrasonic aggregation. Such approaches can actively assemble gold nanorods in 1-2 s and achieved highly sensitive (6.15 × 10-13 M) SERS detection of COVID-19 biomarkers in nanoliter (10-7 L) samples within 5 min. We further demonstrated the high stability, repeatability, and selectivity of the platform, and validated its potential for the detection of throat swab samples. This simple, portable, and ultra-trace integrated active enrichment detection platform is a promising diagnostic tool for the direct and rapid detection of COVID-19.

Medical emergency calls and calls for central nervous system symptoms during the COVID-19 outbreak in Hangzhou, China.

Background: Since January 2020, the continuous and severe COVID-19 epidemic has ravaged various countries around the world and affected their emergency medical systems (EMS). The total number of emergency calls and the number of emergency calls for central nervous system (CNS) symptoms during the 2020 COVID-19 outbreak in Hangzhou, China (January 20-March 20) were investigated, and it was investigated whether these numbers had decreased as compared with the corresponding period in 2019. Methods: The number of daily emergency calls, ambulance dispatches, and rescues at the Hangzhou Emergency Center (HEC) was counted. The CNS symptoms considered in this study included those of cerebrovascular diseases, mental and behavioral disorders, and other neurological diseases. Results: It was found that, during the 2020 study period, the number of emergency calls was 33,563, a decrease of 19.83% (95% CI: 14.02-25.41%) as compared to the 41,863 emergency calls in 2019 (P < 0.01). The number of ambulances dispatched was 10,510, a decrease of 25.55% (95 %CI: 18.52-35.11%) as compared to the 14,117 ambulances dispatched in 2019 (P < 0.01). The number of rescues was 7,638, a decrease of 19.67% (95% CI: 16.12-23.18%) as compared with the 9,499 rescues in 2019 (P < 0.01). It was also found that the number of emergency calls related to CNS symptoms, including symptoms of cerebrovascular diseases, mental and behavioral disorders, and other neurological diseases, was significantly reduced (P < 0.01). Conclusion: The total number of medical emergency calls and the number of emergency calls for CNS symptoms occurring in a large city in China decreased significantly during the COVID-19 epidemic.

Integrated microdroplet array platform with temperature controller and micro-stirring for ultra-fast SARS-CoV-2 detection.

The outbreak of COVID-19 has created a huge challenge to global health systems. Experience in fighting the epidemic shows that the development of a rapid and sensitive POCT diagnostic platform for SARS-CoV-2 that can be deployed in situ is crucial to contain the outbreak. Here, we have developed a portable microdroplet detection platform that integrated temperature controller and micro-stirring for high-throughput and ultrafast COVID-19 diagnosis. Such a device uses a p-n junction (PN junction) as the temperature controller to adjust the temperature in a single microdroplet independently and precisely, ensuring the amplification of reverse transcription loop-mediated isothermal amplification (RT-LAMP). Meanwhile, the platform incorporates an ultrasonic micro-stirring unit, greatly increasing the interaction between RT-LAMP molecules and accelerating the amplification. The results show good linearity over a wide linear range (1 to 105 copies/µL) and low LOD (0.48 copy/µL). Our method reports in only 6.1 min for high-viral load samples, and combines with sample preparation, the total detection process could be done within 30 min. Such a portable and fully integrated microdroplet molecular diagnostic platform is a promising tool for point-of-care diagnosis of COVID-19 and other infectious diseases in resource-limited settings.

Establishment of ELISA for detecting porcine epidemic diarrhea virus specific SIgA in mucus

The aim of this study is to establish an indirect ELISA technique for detecting the SIgA antibody against porcine epidemic diarrhea virus (PEDV) to evaluate its mucosal immunity. Firstly, the S1D gene (534-789 aa) of PEDV was cloned into the pET-28a(+) vector, and induced in Escherichia coli BL21 (DE3) by IPTG, the product of which was in the form of inclusion bodies. According to Western-blot, the target protein S1D with antigenic activity was 32 ku in molecular weight and could be well detected. Then, the S1D protein was denatured by 8 mol/L urea, purified and gradient as the coating antigen to establish an indirect ELISA for detecting the PEDV specific SIgA antibody in nasal or oral mucus by optimizing conditions. And the optimal antigen coating concentration of ELISA was 2 micro g mL, the working concentrations of nasal mucus was 1:1 and the optimal blocking solution was 50 g/L skimmed milk, while the working concentrations and optimal blocking solution were 1:2 and 30 g/L BSA in oral mucus, the working concentrations of the enzyme-labeled antibody was 1:2 000 in nasal and oral mucus. Finally, 84 samples of oral and nasal mucus from immunized pigs were detected by S1D of ELISA, and the coincidence rate could reach 95.2% compared with purified PEDV of ELISA. In conclusion, the indirect ELISA established in this study provided a quick, simple, sensitive, and specific method to detect PEDV specific SigA for evaluating the level of PEDV mucosal immunity.

Explore the attitudes of children and adolescent parents towards the vaccination of COVID-19 in China.

BACKGROUND: With the increasing incidence of asymptomatic carriers or milder symptoms, children and adolescents are likely to become a silent source of infection. In view of the efficacy and safety of vaccines in the treatment of novel Coronavirus pneumonia, population-wide vaccination will be an inevitable trend to control the spread of COVID-19. However, there is no survey on the attitudes of Chinese parents of children and adolescents towards their children's COVID-19 vaccination. METHODS: We used online questionnaires to find out the attitudes of Chinese parents toward their children's immunization against COVID-19. Logistic regression was used to explore the influencing factors. RESULTS: A total of 2019 parents participated in the survey. Overall, 74.38% parents said they would actively get vaccinated, 8.90% refused to get vaccinated, 4.60% said they would delay vaccination and 12.12% were still undecided. CONCLUSIONS: In general, Chinese parents have a high desire to be vaccinated against COVID-19, and most parents have a positive attitude towards their children's vaccination. However, many people still hesitate or even refuse to be vaccinated. Education background, attitudes towards children's vaccination, children's age, recent illness and other factors have a certain impact on Chinese parents of children and adolescents towards their children's COVID-19 vaccination.

Enhanced Isothermal Amplification for Ultrafast Sensing of SARS-CoV-2 in Microdroplets.

Rapid and high-throughput screening is critical to control the COVID-19 pandemic. Recombinase polymerase amplification (RPA) with highly accessible and sensitive nucleic acid amplification has been widely used for point-of-care infection diagnosis. Here, we report an integrated microdroplet array platform composed of an ultrasonic unit and minipillar array to enhance the RPA for ultrafast, high-sensitivity, and high-throughput detection of SARS-CoV-2. On such a platform, the independent microvolume reactions on individual minipillars greatly decrease the consumption of reagents. The microstreaming driven by ultrasound creates on-demand contactless microagitation in the microdroplets and promotes the interaction between RPA components, thus greatly accelerating the amplification. In the presence of microstreaming, the detection time is 6-12 min, which is 38.8-59.3% shorter than that of controls without microstreaming, and the end-point fluorescence intensity also increased 1.3-1.7 times. Furthermore, the microagitation-enhanced RPA also exhibits a lower detection limit (0.42 copy/µL) for SARS-CoV-2 in comparison to the controls. This integrated microdroplet array detection platform is expected to meet the needs for high-throughput nucleic acid testing (NAT) to improve the containment of viral transmission during the epidemic, as well as provide a potential platform for the timely detection of other pathogens or viruses.

Efficacy and safety of three new oral antiviral treatment (molnupiravir, fluvoxamine and Paxlovid) for COVID-19：a meta-analysis.

BACKGROUND: The coronavirus disease (COVID-19) epidemic has not been completely controlled. Although great achievements have been made in COVID-19 research and many antiviral drugs have shown good therapeutic effects against COVID-19, a simple oral antiviral drug for COVID-19 has not yet been developed. We conducted a meta-analysis to investigate the improvement in mortality or hospitalization rates and adverse events among COVID-19 patients with three new oral antivirals (including molnupiravir, fluvoxamine and Paxlovid). METHODS: We searched scientific and medical databases, such as PubMed, Web of Science, Embase and Cochrane Library for relevant articles and screened the references of retrieved studies on COVID-19. RESULTS: A total of eight studies were included in this study. The drug group included 2440 COVID-19 patients, including 54 patients who died or were hospitalized. The control group included a total of 2348 COVID-19 patients, including 118 patients who died or were hospitalized. The overall odds ratio (OR) of mortality or hospitalization was 0.33 (95% confidence interval [CI], 0.22-0.49) for COVID-19 patients in the drug group and placebo group, indicating that oral antiviral drugs were effective for COVID-19 patients and reduced the mortality or hospitalization by approximately 67%. CONCLUSIONS: This study showed that three novel oral antivirals (molnupiravir, fluvoxamine and Paxlovid) are effective in reducing the mortality and hospitalization rates in patients with COVID-19. In addition, the three oral drugs did not increase the occurrence of adverse events, thus exhibiting good overall safety. These three oral antiviral drugs are still being studied, and the available data suggest that they will bring new hope for COVID-19 recovery and have the potential to be a breakthrough and very promising treatment for COVID-19.KEY MESSAGESMany antiviral drugs have shown good therapeutic effects, and there is no simple oral antiviral drug for COVID-19 patients.Meta-analysis was conducted for three new oral antivirals to evaluate the improvement in mortality or hospitalization rates and adverse events among COVID-19 patients.We focussed on three new oral Coronavirus agents (molnupiravir, fluvoxamine and Paxlovid) and hope to provide guidance for the roll-out of oral antivirals.

Food Safety Knowledge, Attitudes, and Self-Reported Practices Among Medical Staff in China Before, During and After the COVID-19 Pandemic.

PURPOSE: To compare food safety knowledge, attitudes, and self-reported practices among medical staff in China before, during, and after the COVID-19 pandemic. PATIENTS AND METHODS: The questionnaire was anonymous. All respondents were Chinese medical personnel. A Chi-square contingency table was used to compare the knowledge and attitudes of Chinese medical staff before, during and after COVID-19. R statistical software (v4.0.0) was used for analysis. RESULTS: A total of 1431 valid responses (57.3% from female respondents) were included in our analysis. Medical professionals were geographically distributed as follows: eastern China, 55.5%; central China, 19.7%; western China, 24.1%; Hong Kong, Macau, or Taiwan, 0.05%. Medical professionals reported that they paid greater attention to food safety after the COVID-19 pandemic compared with before the epidemic. Self-reported knowledge of and attitudes toward food safety among medical staff were significantly different before, during, and after the COVID-19 pandemic (both P<0.001). CONCLUSION: After the COVID-19 pandemic, medical professionals paid increasing attention to food safety, which is a clinically important change. Because medical professionals can influence public understanding of food safety, their increased attention to this subject may enable them to promote food safety knowledge more actively in their work. This may in turn promote a better understanding of food safety and protect the health of the general public.

Exploring the Pattern of Early COVID-19 Transmission Caused by Population Migration Based on 14 Cities in Hubei Province, China.

BACKGROUND AND AIM: Relevant studies show that population migration has a great impact on the early spread of infectious diseases. Therefore, it is important to explore whether there is an explicit relationship between population migration and the number of confirmed cases for the control of the COVID-19 epidemic. This paper mainly explores the impact of population migration on early COVID-19 transmission, and establishes a predictive nonlinear mathematical model to predict the number of early cases. METHODS: Data of confirmed cases were sourced from the official website of the Municipal Health Committee, and the proportions of migration from Wuhan to other cities were sourced from the Baidu data platform. The data of confirmed cases and the migration proportions of 14 cities in Hubei Province were collected, the COVID-19 cases study period was determined as 10 days based on the third quartile of the interval of the incubation period, and a non-linear mathematical model was constructed to clarify the relationship between the migration proportion and the number of confirmed COVID-19 cases. Finally, eight typical regions were selected to verify the accuracy of the model. RESULTS: The daily population migration rates and the growth curves of the number of confirmed cases in the 14 cities were basically consistent, and Pearson's correlation coefficient was 0.91. The specific mathematical expression of 14 regions is . In each of the fourteen cities, The nonlinear exponential model structure is as follows:. It was found that the R 2 values of the fitted mathematical model were greater than 0.8 in all studied regions, excluding Suizhou (p < 0.05). The established mathematical model was used to fit eight regions in China, and the correlations between the predicted and actual numbers of confirmed cases were greater than 0.9, excluding that of Hebei Province (0.82). CONCLUSION: The study found that population migration has a positive and significant impact on the spread of COVID-19. Modeling COVID-19 risk may be a useful strategy for directing public health surveillance and interventions. Restricting the migration of the population is of great significance to the joint prevention and control of the pandemic worldwide.