Covid-19 in New York #4 (Sept 5)

There are two colleges here in Ithaca. Both planned to have classes on campus. Ithaca College (the smaller one) changed their mind a few weeks ago. They will be online-only for the Fall semester. Cornell went ahead with their reopening plans, and classes started on Wednesday. The Vet School laboratories are testing all undergraduates twice a week, which sounds great in theory.

Three weeks ago, there were 7 active cases of Covid-19 in the county. A week ago there were 19. Yesterday, there were 70. Most cases happened because students had parties without masks or social distancing. Who could possibly have suspected that might happen? /s

Maybe everyone will get scared, and change their behavior. More likely, there will be enough cases to trigger an automatic shut-down, per NYS regulations. We’ll see.

Meanwhile in the rest of the US, the State Rt tracker shows wavy curves for every single state. Today the majority of states are positive. Sometimes the majority are negative. It seems to vary on a few-week cycle. Back in April I compared state responses to skidding on icy roads. Because of the feedback delay, it’s easy to lose control and end up in a ditch.

Luckily, that isn’t happening with Covid-19. Most states seem to be converging on a Rt value close to 1. That’s probably the ideal growth rate, as long as the case count is low: the best balance between health and economic activity. I guess it also applies to ice and snow: most drivers in the North eventually figure out how to slow down the feedback cycle and stay on the road.

Globally, infections are also at a steady state, with about a million new infections every 4 days. Much of Europe is starting to see early stages of exponential growth, again. It’s going to be a long haul.

I’m still working on an Excel spreadsheet that calculates Covid-19 risk. There are many studies with useful info, but nothing that translates directly into hourly risk. It will require some assumptions and guesswork to get it calculating accurately.

Covid-19 risk is mostly a matter of HVAC. The amount of virus you inhale is equal to the number of people nearby, times the % that are infected, then divided by the volume of air and the number of air changes per hour.

At least a dozen case studies have been published: cruise ships, a Seattle choir practice, a Maine wedding, church events. I have been using Google maps and other sources to estimate building sizes. Air changes is totally a guess.

The biggest uncertainty was expressed best by Dr. Gregory House: “everybody lies”. Folks don’t want to miss work, or they really need a pack of cigs, so they get into public space even though they are shedding virus into the air. Odds are good that they don’t wear a mask. They avoid testing and don’t get into the official data, so the math is more difficult. Everyone’s lives are more difficult.

Dennis Kolva
Programming Director
TurtleSoft.com

Author: Dennis Kolva

Programming Director for Turtle Creek Software. Design & planning of accounting and estimating software.