Now a research team at Columbia University has built a mathematical model that gives a much more complete — and scary — picture of how much virus is circulating in our communities.

It estimates how many people are never counted because they never get tested. And it answers a second question that is arguably even more crucial — but that until now has not been reliably estimated: On any given day, what is the total number of people who are actively infectious? This includes those who may have been infected on previous days but are still shedding virus and capable of spreading disease.

The model’s conclusion: On any given day, the actual number of active cases — people who are newly infected or still infectious — is likely ten times that day’s official number of reported cases…

So this is the next step to Shaman’s model: He estimate that the number of people actively shedding virus on any given day is about 10 times the number of daily new reported cases.

How many people does this add up to? Well, on the worst day for reported new cases so far — Jan. 2 — 91 out of every 100,000 people in the U.S. tested positive. But Shaman estimates that on that same day 998 per 100,000 people were actually actively shedding the virus.