Face mask use in the general population and optimal resource allocation during the COVID-19 pandemic

Face mask use in the general population and optimal resource allocation during the COVID-19 pandemic

MD: Etude chinoise sur l' impact du port de masque dans la population, via des projections épidémiologiques, avec 65% de diminution de mortalité attendue si 15% de la population portait un masque empêchant 75% de passage des flux d’air (les masques chirurgicaux ayant une efficacité minimale réglementaire de 78%). Ils montrent aussi qu’en cas de faible ressource en masque, la distribution préférentielle aux personnes à risque de forme sévère comparativement à une distribution réservée aux patients symptomatiques avait un plus fort impact sur la mortalité (probablement en raison de l’importance des cas asymptomatique, la protection en « bout de la chaîne » prévalant alors)

Understanding COVID-19: what does viral RNA load really mean?

Understanding COVID-19: what does viral RNA load really mean?

In The Lancet Infectious Diseases, Francois-Xavier Lescure and colleagues1 describe the first cases of coronavirus disease 2019 (COVID-19) in Europe, which were reported in France. The detailed clinical features of five patients with COVID-19 are aligned with the quantitative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral RNA load from nasopharyngeal and other selected sampling sites. Previous studies in patients with SARS, Middle East respiratory syndrome (MERS), and COVID-19 generally provide insufficient detail to allow examination of the relationship between individual patient clinical course and viral RNA load.2–4 Although patient numbers are small, the authors provide the first COVID-19 time series correlating viral RNA load and detailed clinical manifestations.1 Importantly, the dataset is provided in sufficient detail so it could be readily combined with future similar studies for deeper analysis.

On the origin and continuing evolution of SARS-CoV-2

On the origin and continuing evolution of SARS-CoV-2

The SARS-CoV-2 epidemic started in late December 2019 in Wuhan, China, and has since impacted a large portion of China and raised major global concern. Herein, we investigated the extent of molecular divergence between SARS-CoV-2 and other related coronaviruses. Although we found only 4% variability in genomic nucleotides between SARS-CoV-2 and a bat SARS-related coronavirus (SARSr-CoV; RaTG13), the difference at neutral sites was 17%, suggesting the divergence between the two viruses is much larger than previously estimated. Our results suggest that the development of new variations in functional sites in the receptor-binding domain (RBD) of the spike seen in SARS-CoV-2 and viruses from pangolin SARSr-CoVs are likely caused by mutations and natural selection besides recombination. Population genetic analyses of 103 SARS-CoV-2 genomes indicated that these viruses evolved into two major types (designated L and S), that are well defined by two different SNPs that show nearly complete…