As the number of diagnosed covid cases in this country approaches one million, I have to remind myself: not everyone who gets sick stays sick.
The total number of American diagnosed with the virus increases by about 30K every day. Based on the NY immunity survey, multiply that number tenfold to estimate the actual incidence: make it 300K new infections daily, or 2M new infections weekly.
How long does someone who contracts the virus stay contagious? Since the verdict is still out, I’ll be cautious: 3 weeks.
So there are about 2M x 3 weeks = 6 million Americans who are presently infected and contagious.
For the past 3 weeks the rate of new infections has plateaued. The 2M new cases added to the roster every week are counterbalanced by 1.9M cases who got sick 3 weeks ago and who have recovered, plus 0.1M who have died. Either way, the 3-week-old cases are no longer contagious.
About 330 million people live in the US. 6M/330M = 1.8% — that’s the percentage of people out there who are presently infected and contagious. As long as the new infection rate remains stable, so will the 1.8% who are contagious at any given time.
When I go for a walk, each random person I encounter has about a 2% likelihood of being presently covid-positive. Not bad.
Say I were to go shopping at a grocery store occupied by 100 people: odds are that 2 of them would be covid-positive. That wouldn’t be a bad risk if everyone in the store were to stay in one place: — then the likelihood of my being positioned within 6 feet of either of those two disease carriers would be small. But everyone just keeps moving up and down the aisles, passing me and coming up from behind, blocking my progress in temporary clumps and jamming up the checkout lanes…
There are regional differences. Using these same calculations, fewer than 1 percent of my fellow North Carolinians are currently infected.
The downside: as long as the infection rates remain plateaued, the law of large numbers will prevail, with nearly everyone getting the chance to spend their own personal three weeks as a member of that select minority.