In 4 US state prisons, 3,300 inmates test positive, 96% without symptoms
I see a lot of people dismissing the shared air space & HVAC systems as possible vectors of infection besides close contact, but you have to remember a very important factor:Droplets exist in a continuum, not a binary of big == fall to ground, small == stay in the air. There's a range, and as they get smaller they stay in the air longer.Large droplets (>50 μm in diameter) settle on the ground almost immediately, and intermediate-sized droplets (10–50 μm) settle within several minutes. Small particles ( [0]As such, while particles that stay aloft longer may not exists in sufficient quantities when it is just one infected, or a few infected inmates, that changes with the # of infected. With each infected inmate the concentrations of those small particles will increase.Let's say that normally the small particles exist at 3% the necessary quantity to infect another person. Then 33 inmates and staff get sick through close contact, and all of a sudden the concentrations of small droplets is sufficient to infect people. You hit a critical mass, and each additional infection only makes it worse, creating a rapid downward spiral.[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4147198/