COVID-19 Outbreak at an Overnight Summer School Retreat ― Wisconsin, July–August 2020 Morbidity and Mortality Weekly Report. It looks to me like the Summer School actually did make an effort at social distancing, though obviously not enough. “Classes were held in outdoor pavilions with approximately 20 students per class seated <6 feet (<2 m) apart at tables. Teachers wore masks during class and were socially distanced from students at all times.” This sentence caught my eye: “All illnesses were mild to moderate, and no hospitalizations or deaths occurred.” This makes me think that there really may be a dose-response relationship.
Effectiveness of Face Masks in Preventing Airborne Transmission of SARS-CoV-2 American Society for Microbiology. This paragraph caught my eye: “It has been reported that the stability of the virus in the air changes depending on the droplet/aerosol components, such as inorganics, proteins, and surfactants, suggesting that the permeation efficiency of masks is also affected by the components of viral droplets/aerosols…. Further detailed analysis will be required to reveal the precise relationship between the protective efficiency of masks and the components of viral droplets/aerosols.”
BLACK: no evidence; GREEN: Recommended (strong); YELLOW: recommended (weak); RED: not recommended. LIGHT BLUE: not mentioned in each country guidelines. DIVIDED COLOR in a box (Peru): Infectious Disease society gives an opposite recommendation to official government guidelines.
Robust neutralizing antibodies to SARS-CoV-2 infection persist for months Science. From the abstract: “Here we report that the vast majority of infected individuals with mild-to-moderate COVID-19 experience robust IgG antibody responses against the viral spike protein, based on a dataset of 30,082 individuals screened at Mount Sinai Health System in New York City. We also show that titers are relatively stable for at least a period approximating 5 months and that anti-spike binding titers significantly correlate with neutralization of authentic SARS-CoV-2.”