[Experience in emergency response to 2019-nCoV positive cases in an international test competition].

Objective: To analyze the performance of emergency response to 2019 novel coronavirus (2019-nCoV) positive cases in an international test competition in an Winter Olympic Game venue and provide evidences for the COVID-19 prevention and control in similar competitions. Methods: A retrospective analysis on the epidemiological investigation and nucleic acid test results of the cases, the implementation of prevention and control measures, including the communication with sport teams and others, was conducted. Results: The positive cases of 2019-nCoV among entering people were detected before entry, at airport, hotel and venue. Two positive cases were reported before entry, 2 positive cases infected previously and 3 asymptomatic cases were reported after the entry. The venue public health team and local CDC conducted epidemiological investigation and contact assessment jointly in a timely and efficient manner. No local secondary transmission occurred, but the nucleic acid test results of positive persons fluctuated, posing serious challenges to the implementation of prevention and control measures. Conclusion: In large scale international competition, there is high risk of imported COVID-19. It is necessary to fully consider the fluctuation of nucleic acid test results, the criteria for determination and cancellation of positive results and give warm care to positive cases in the emergency response.

Building-level wastewater surveillance using tampon swabs and RT-LAMP for rapid SARS-CoV-2 RNA detection

Wastewater surveillance for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA has demonstrated useful correlation with both coronavirus disease 2019 (COVID-19) cases and clinical testing positivity at the community level. Wastewater surveillance on college campuses has also demonstrated promising predictive capacity for the presence and absence of COVID-19 cases. However, to date, such monitoring has most frequently relied upon composite samplers and reverse transcription quantitative PCR (RT-qPCR) techniques, which limits the accessibility and scalability of wastewater surveillance, particularly in low-resource settings. In this study, we trialed the use of tampons as passive swabs for sample collection and reverse transcription loop-mediated isothermal amplification (RT-LAMP), which does not require sophisticated thermal cycling equipment, to detect SARS-CoV-2 RNA in wastewater. Results for the workflow were available within three hours of sample collection. The RT-LAMP assay is approximately 20 times less analytically sensitive than RT-droplet digital PCR. Nonetheless, during a building-level wastewater surveillance campaign concurrent with independent weekly clinical testing of all students, the method demonstrated a three-day positive predictive value (PPV) of 75% (excluding convalescent cases) and same-day negative predictive value (NPV) of 80% for incident COVID-19 cases. These predictive values are comparable to that reported by wastewater monitoring using RT-qPCR. These observations suggest that even with lower analytical sensitivity the tampon swab and RT-LAMP workflow offers a cost-effective and rapid approach that could be leveraged for scalable building-level wastewater surveillance for COVID-19 potentially even in low-resource settings.

Within- and between-Day Variability of SARS-CoV-2 RNA in Municipal Wastewater during Periods of Varying COVID-19 Prevalence and Positivity

Wastewater surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA is being used to monitor Coronavirus Disease 2019 (COVID-19) trends in communities;however, within- and between-day variation of SARS-CoV-2 RNA concentration in primary influent remains largely uncharacterized. In the current study, grab sampling of primary influent was performed every 2 h over two 24-h periods at two wastewater treatment plants (WWTPs) in northern Indiana, USA. The recovery efficiency of endogenous SARS-CoV-2 RNA in wastewater was confirmed to be similar to the recovery efficiency of the process control, bovine respiratory syncytial virus (BRSV). Recovery-corrected SARS-CoV-2 RNA concentrations in primary influent indicate diurnal loading patterns and confirm monitoring dependent on grab samples should target daytime periods with high fecal loading. Importantly, manual compositing performed at the WWTP resulted in concentrations that were consistently lower than grab sample averages indicating potential bias. Uncorrected, recovery-corrected, and pepper mild mottle virus (PMMoV)-normalized SARS-CoV-2 RNA concentrations demonstrated an ordinal agreement with increasing clinical COVID-19 positivity but not COVID-19 cases. In areas where geolocated COVID-19 case data are not available, the COVID-19 positivity rate could provide a useful county-level metric for comparison with wastewater. Nonetheless, large variation both within- and between-days may preclude robust quantitative analyses beyond correlation.

[Experience and thinking on the normalization stage of prevention and control of COVID-19 in China].

COVID-19 is an important public health issue of great concern at home and abroad, and it is still in the state of global pandemic. During the normalization stage of prevention and control of the epidemic of COVID-19, China effectively controlled the outbreak and spread of the epidemic by adopting the strategy of "import of external prevention and rebound of internal prevention", and effectively reduced the occurrence of death cases. The social economy recovered quickly, and various measures were highly recognized by the public, and the positive trend of the epidemic continued to consolidate. At present, although the spread of the local epidemic has been basically stopped, the international epidemic continues to rise rapidly, and the pressure of "imported prevention and control" in China continues to increase. Considering the characteristics of the normalization of epidemic prevention and control and the particularity of the virus, the connotation of the normalization of epidemic prevention and control should be understood scientifically. The prevention and control goal of the epidemic in the normalization stage should be to maximize early detection, early treatment and early disposal, and resolutely prevent the continuous spread of the epidemic in communities, that is, to prevent the infection as much as possible, and resolutely prevent the rebound (sustained spread in communities), rather than "zero infection". The prevention and control policy of "timely detection, rapid disposal, precise management and control, and effective treatment" has been implemented in various localities, and a series of effective and regular experience in prevention and control has been formed in the practice of prevention and control. Winter and spring are the key periods for the prevention and control of the epidemic. We should continue to work together to prevent and control the epidemic, fulfill the responsibilities of all parties, and prevent and control the epidemic in a scientific and effective way.

Therapeutic Drug Monitoring and Individualized Medication of Ribavirin

Ribavirin is a widely used nucleoside antiviral drug. During the epidemic of coronavirus disease 2019 (COVID-19), ribavirin was recommended for empirical treatment in the Clinical Management of Human Infection with COVID-19 (trial guidance v6). However, due to the large inter-individual variations in dose-response relationship, and extremely long terminal half time, it is necessary to perform therapeutic drug monitoring and individualized dose adjustment for ribavirin in special populations. In this article, the pharmacokinetics and therapeutic drug monitoring of ribavirin in different populations are reviewed in order to provide reference for clinical rational use and individualized medication of ribavirin for treatment of COVID-19. Copyright 2020 by the Chinese Pharmaceutical Association.

[Contribution of asymptomatic and pre-symptomatic cases of COVID-19 in spreading virus and targeted control strategies].

The asymptomatic carrier state of COVID-19 has become a topic of concern for preventing the rebound of possible epidemic. This review describes and defines the COVID-19 asymptomatic carrier state and outlines the methods for identifying, counting and reporting of these cases. The author elaborates that the asymptomatic carrier state can be further divided into asymptomatic infection and pre-symptomatic infection after extended follow-up based on the nature of the disease progression. The author presents the limited available data about the infectivity of asymptomatic and pre-symptomatic cases and their possible contributions to the overall epidemic of COVID-19 observed so far in China. Challenges of a possible second epidemic wave of COVID-19 caused by asymptomatic and pre-symptomatic cases are discussed and suggestions for control strategies and scientific research are provided.

[Analysis of application of herd immunity as a control strategy for COVID-19].

Novel coronavirus spreads very fast and is not easy to control. It has spread over 200 countries or territories. China has taken action to implement containment strategies, including active COVID-19 case finding, tracing, and 14-day quarantine of close contacts, and home isolation of 1.39 billion of people countrywide for at least 2 weeks, etc. The combination of these strategies has brought the epidemic under control in China. The United Kingdom had deliberately not implemented containment measures for a while, instead opting to allow herd immunity strategy to develop over time. This is a "do-nothing" strategy whereby the virus is allowed to move through communities naturally until certain proportion of people has been infected, and the epidemic ends without intervention. The author assesses containment strategies versus this herd immunity strategy in real-world application to the COVID-19 epidemic. The author suggests an innovative strategy to balance controlling the epidemic and preventing impediment to economic and social development.