How many people are infectious in the United States right now?

My best guess is that 31,030,230 total people are infectious right now. Put another way, that’s 95 out of 1,000 (9.45%). What are my assumptions?

Based on CDC Planning Scenarios and public statements:

• 30-50% of infected people are asymptomatic

• New York City testing showed antibody rates higher than that CDC estimate (added on 22 August 2020)

• Serology tests aren’t reliable yet, but a significant multiple of detected cases are the actual probable case count, so currently using 5 times the case count for probable cases

• Median time between exposure and symptoms is 6 days

• Median time from symptom onset to death is 22 days

Start with probable cases, which is positive test results times 8 (changed from 5 on 22 August 2020 because of NYC data). In the US, that number is currently 410,648,640 total. Then, compute recoveries, probably cases from 22 days ago minus current deaths (1,128,874 total), currently 374,266,462 total. Currently infectious people is then probable cases from 6 days ago minus current recoveries.

Another option to back check this is to look at this recent paper estimating unobserved covid cases. It estimates approximately 100,000 covid infections by early March, about 2-3 weeks earlier than my graphs move, but fairly consistent with my delayed assumptions described above. I am most certainly not an epidemiologist, so the goal is to stay roughly within an order of magnitude.

Note: imported from Covid Proxima. Click here to see all the interactive elements.