# The mathematics of the Chinese Flu

[Editor’s Note: We are not permitted to call the Wuhan Virus the Wuhan Virus because that would be cismisogynistic or something. So this blog is referring to it as the Chinese Flu.]

For those so inclined, we can reduce the virus to numbers.

How canceled events and self-quarantines save lives, in one chart

A disastrous inundation of hospitals can likely be averted with protective measures we’re now seeing more of — closing schools, canceling mass gatherings, working from home, self-quarantine, self-isolation, avoiding crowds — to keep the virus from spreading fast.

Epidemiologists call this strategy of preventing a huge spike in cases “flattening the curve,” and it looks like this:

The Elegant Mathematics of Social Distancing.

From a mathematical perspective, determining how big a crowd is safe depends on a couple of key questions: How many people in a given area are infected with the disease? And how big is the event? If you know those things, you can estimate the probability of someone getting infected at the event. An elegant “Covid-19 Event Risk Assessment Planner” by the Georgia Tech quantitative biologist Joshua Weitz makes the following calculation: If, say, 20,000 cases of infection are actively circulating the US (far more than are known so far), and you host a dinner party for 10 folks, there’s a 0.061 percent chance that an attendee will be infected. But if you attend a 10,000-person hockey match, there’s a 45 percent chance.

COVID-19 Event Risk Assessment Planner

The mathematics for calculating the probability of exposure given the number of carriers in a population and group size aren’t difficult but they can be surprising. Even a low number of carriers can generate a relatively high probability for reasonably sized groups. For example, assume you run a firm of 1000 people in the San Francisco Bay Area (population 8 million.) Let’s suppose that there are just 500 carriers in the area. In this case, assuming random draws, the probability that at least one of your employees is a carrier is 6%. You can run your own calculations at Wolfram Alpha following this format:

p=8000000, c=500, g=1000, 1-1(1-c/p)^g //N

where p is the population size, c is the number of carriers, g is the group size and the //N at the end isn’t a division but a command to Wolfram Alpha to give you a numerical answer.

Coronavirus expert says he knows when the virus ‘will burn itself out,’ according to leaked analysis

“Sunlight will cut the virus’ ability to grow in half so the half-life will be 2.5 minutes and in the dark it’s about 13 to 20 [minutes],” Nicholls said. “Sunlight is really good at killing viruses.” For that reason, he also added that he doesn’t expect areas such as Australia, Africa and the Southern hemisphere to see high rates of infection because they are in the middle of summer.

Regarding temperatures, Nicholls said the warmer the better for stopping the spread of the virus, according to the transcript of the conference call. “The virus can remain intact at 4 degrees (39 degrees Fahrenheit) or 10 degrees (50 F) for a longer period of time,” Nicholls said, referring to Celsius measurements, according to the transcript. “But at 30 degrees (86 degrees F) then you get inactivation. And high humidity — the virus doesn’t like it either,” he added, the transcript of the call showed.

How long can the new coronavirus last on surfaces?

How long can the new coronavirus linger on surfaces, anyway? The short answer is, we don’t know. A new analysis found that the virus can remain viable in the air for up to 3 hours, on copper for up to 4 hours, on cardboard up to 24 hours and on plastic and stainless steel up to 2 to 3 days. However, this studyhas not yet yet been peer-reviewed.

Another study concluded that if this new coronavirus resembles other human coronaviruses, such as its “cousins” that cause SARS and MERS, it can stay on surfaces — such as metal, glass or plastic — for as long as nine days (In comparison, flu viruses can last on surfaces for only about 48 hours.)

Ohio Official Who Claimed 100,000 Covid-19 Cases in the State Says She Was ‘Guesstimating’

The director of Ohio’s Department of Health, Amy Acton, shocked a lot of people on Thursday when she said in a press conference that she believed 100,000 Ohioans had already contracted Covid-19. The Columbus Dispatch offered effusive praise of Acton for being a “voice of knowledge.” What an incredible human being, to let her humanity “shine through” like that. Brings a tear to my eye, it does. But Director Acton forgot to mention a small detail about her Apocalypse Now statement; it wasn’t true.

~ Calash