Background: An ongoing outbreak of coronavirus disease 2019 (COVID-19) has spread around the world. It is debatable whether asymptomatic COVID-19 virus carriers are contagious. We report here a case of the asymptomatic patient and present clinical characteristics of 455 contacts, which aims to study the infectivity of asymptomatic carriers. Material and methods: 455 contacts who were exposed to the asymptomatic COVID-19 virus carrier became the subjects of our research. They were divided into three groups: 35 patients, 196 family members and 224 hospital staffs. We extracted their epidemiological information, clinical records, auxiliary examination results and therapeutic schedules. Results: The median contact time for patients was four days and that for family members was five days. Cardiovascular disease accounted for 25% among original diseases of patients. Apart from hospital staffs, both patients and family members were isolated medically. During the quarantine, seven patients plus one family member appeared new respiratory symptoms, where fever was the most common one. The blood counts in most contacts were within a normal range. All CT images showed no sign of COVID-19 infection. No severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections was detected in 455 contacts by nucleic acid test. Conclusion:In summary, all the 455 contacts were excluded from SARS-CoV-2 infection and we conclude that the infectivity of some asymptomatic SARS-CoV-2 carriers might be weak. IntrodutionThe emergence of the coronavirus disease 2019 (COVID-19) since early December 2019, has spread to many countries recently and sparked world pandemic via mass gathering [1][2][3]. As of March 24, 2020, there have been 334981 confirmed cases and 14652 deaths globally [4].It has been proved that the pathogen of COVID-19 is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has high homology with SARS-CoV [5]. Similar to SARS-CoV, the dominant SARS-CoV-2 transmission mode is human-to-human transmission [6]. Differently, the reproductive number (R0)

The present study compared the efficacy of standard and extended durations of PEG-IFNα-2a monotherapy for treatment of HBeAg-negative Chinese patients with chronic hepatitis B. Patients were randomized to receive standard therapy (n = 38; 48 weeks treatment) or extended therapy (n = 42; 72 weeks treatment). Extended therapy resulted in a significantly higher HBV DNA inhibition at 24 and 48 weeks after the end of treatment, a significantly higher sustained HBV DNA inhibition at the end of treatment, and a significantly lower HBsAg level at 24 and 48 weeks after the end of treatment (P < 0.05 for all comparisons). The HBsAg clearance rate was significantly greater in the extended therapy group than in the standard therapy group at 24 and 48 weeks post-treatment (33.3% vs. 10.5% and 35.7% vs. 10.5%, respectively; P < 0.05 for both). In addition, patients with an increase of more than 1 log10  IU/ml in HBsAg level from baseline to week 24 had a significantly lower level of HBsAg at end of treatment (0.54 ± 1.76 vs. 2.89 ± 1.27, P < 0.001), but a higher level of HBsAg clearance (64.3% vs. 7.6%, P < 0.001). Assessment of HBsAg level at week 24 appears to be a suitable checkpoint. These results indicate that 72 weeks of PEG-IFNα-2a monotherapy benefits HBeAg-negative Chinese patients with chronic hepatitis B who are infected with HBV genotype B or C.

Background and Aims There is scarcity of data in literature regarding the treatment response to sofosbuvir- (SOF-) based therapies in Chinese patients with chronic Hepatitis C Virus (HCV) infection. The aim of this study was to evaluate the efficacy and safety of SOF-based regimens for chronic hepatitis C (CHC) patients without cirrhosis in a real-world setting in mainland China. Methods A total of 226 patients receiving SOF plus daclatasvir (DCV), ledipasvir (LDV), or velpatasvir (VEL) were enrolled from December 2014 to June 2017. The primary observation point was the percentage of patients with a sustained virologic response (SVR) at posttreatment week 12 (SVR12), and all adverse events were monitored during treatment and follow-up period. Results The overall SVR12 rate was 96% (216/226), and individual SVR12 ranged from 93% to 100% in different treatment groups. No significant differences of efficacy were detected between genotypes 1b and 6a (98% for GT 1b versus 100% for GT 6a, P=0.322). Comparing the high success rates in GT 1b and 6a patients, SVR12 was relatively low in GT 3a and 3b patients. A significant difference in efficacy was observed between GT 3 and not GT 3 patients (77% versus 98%, respectively, P<0.001). No significant differences in efficacy were detected among different regimens (93% versus 97% versus 100%, respectively, P=0.153), gender (95% for male versus 96% for female, P=0.655), or baseline HCV RNA lever (96% versus 95%, respectively, P=0.614). Similar SVR rates were also obtained in naïve and previously treated patients (98% versus 93%, respectively, P=0.100). Conclusions NS5B polymerase inhibitor SOF plus one of the NS5A inhibitors, such as DCV, LDV, or VEL for 12 weeks was associated with high SVR12 rates and well tolerated in HCV-infected patients without cirrhosis. Moreover, patients with DAAs failure should be retreated with more effective regimens like SOF/VEL.

β-Bi2O3 particles were synthesized by a polyacrylamide sol-gel method. The sonocatalytic activity of β-Bi2O3 particles was evaluated by degrading Rhodamine B (RhB) under the ultrasonic irradiation, revealing that β-Bi2O3 particles exhibit a good sonocatalytic activity. The effects of various experimental factors including ultrasonic frequency (f), solution temperature (T), catalyst dosage (Ccatalyst) and initial RhB concentration (CRhB) on the sonocatalysis efficiency were investigated. The optimum conditions for sonocatalytic degradation of RhB are obtained to be f=60 kHz, T=40 °C, Ccatalyst=3 g L(-1), and CRhB=5 mg L(-1). The percentage degradation of RhB after sonocatalysis for 90 min is 98.7%. Detected by the photoluminescence technique that of using terephthalic acid as a probe molecule, hydroxyl radicals (OH) are found to be produced on the irradiated by β-Bi2O3 particles. Based on the experimental results, OH radicals are suggested to be the major active species which are responsible for the degradation reaction.

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