Knowledge of and attitudes toward COVID-19 among parents of child dental patients during the outbreak

Abstract: The aim of this study was to evaluate the knowledge of and attitudes toward coronavirus disease 2019 (COVID-19) among the parents of child dental patients in Shenzhen during the outbreak. A structured questionnaire containing 10 questions was used, and each question had 2 or 3 possible answers. The parents of children (aged 0-14 years) who visited the dental department of our hospital last year were eligible to participate in this study. A total of 148 parents were interviewed by telephone in February 2020 by research staff. A total of 94.59% of the parents said they paid high attention to COVID-19 and explained it to their children;66.22% thought the dental department environment was more dangerous than other public places;91.89% believed the dental department had a higher risk of virus infection;and 83.78% said they would take their children to a dental department if the children had a severe toothache. Approximately 81.08% of the parents expressed confidence after we informed them about the preventive measures taken in the dental department to ensure safe treatment for their children. In conclusion, all parents were concerned about COVID-19, and most of them had talked about it with their children often. In addition, a considerable percentage of them would not take their children to the dental department even if they had severe dental pain and thought that the dental environment could be more dangerous than other environments. More information about this topic should be delivered to this population.

Reproducibility and sensitivity of 36 methods to quantify the SARS-CoV-2 genetic signal in raw wastewater: findings from an interlaboratory methods evaluation in the U.S. (preprint)

1In response to COVID-19, the international water community rapidly developed methods to quantify the SARS-CoV-2 genetic signal in untreated wastewater. Wastewater surveillance using such methods has the potential to complement clinical testing in assessing community health. This interlaboratory assessment evaluated the reproducibility and sensitivity of 36 standard operating procedures (SOPs), divided into eight method groups based on sample concentration approach and whether solids were removed. Two raw wastewater samples were collected in August 2020, amended with a matrix spike (betacoronavirus OC43), and distributed to 32 laboratories across the U.S. Replicate samples analyzed in accordance with the projects quality assurance plan showed high reproducibility across the 36 SOPs: 80% of the recovery-corrected results fell within a band of +/- 1.15-log10 genome copies/L with higher reproducibility observed within a single SOP (standard deviation of 0.13-log10). The inclusion of a solids removal step and the selection of a concentration method did not show a clear, systematic impact on the recovery-corrected results. Other methodological variations (e.g., pasteurization, primer set selection, and use of RT-qPCR or RT-dPCR platforms) generally resulted in small differences compared to other sources of variability. These findings suggest that a variety of methods are capable of producing reproducible results, though the same SOP or laboratory should be selected to track SARS-CoV-2 trends at a given facility. The methods showed a 7-log10 range of recovery efficiency and limit of detection highlighting the importance of recovery correction and the need to consider method sensitivity when selecting methods for wastewater surveillance.

A Two-Phase Dynamic Contagion Model for COVID-19 (preprint)

In this paper, we propose a continuous-time stochastic intensity model, namely, two-phase dynamic contagion process(2P-DCP), for modelling the epidemic contagion of COVID-19 and investigating the lockdown effect based on the dynamic contagion model introduced by Dassios and Zhao (2011). It allows randomness to the infectivity of individuals rather than a constant reproduction number as assumed by standard models. Key epidemiological quantities, such as the distribution of final epidemic size and expected epidemic duration, are derived and estimated based on real data for various regions and countries. The associated time lag of the effect of intervention in each country or region is estimated. Our results are consistent with the incubation time of COVID-19 found by recent medical study. We demonstrate that our model could potentially be a valuable tool in the modeling of COVID-19. More importantly, the proposed model of 2P-DCP could also be used as an important tool in epidemiological modelling as this type of contagion models with very simple structures is adequate to describe the evolution of regional epidemic and worldwide pandemic.