Within the first minute — “spanish flu or swine flu, it killed about 675 thousand” (in the US):

1918 Spanish Flu historical documentary | Swine Flu Pandemic | Deadly plague of 1918

I’ll keep the math here as simple as I possibly can.
Q1: How many times can 200,000 be doubled, to exceed 675,000?
1doublings —> 400,000
2doublings —> 800,000 (exceeds 675,000)

The 200,000 # deaths in US in near future is based on a model for Covid-19 that assumes we can (possibly, in the short term) slow down and limit its spread in the US to about 3% of the US population, for a while.

Q2: How many times can 3% be doubled, to reach ~50% or ~100% (of US population)?
1doublings —> 6%
2doublings —> 12%
3doublings —> 24%
4doublings —> 48%
5doublings —> 96% (It is likely to stop short of this.)

Q3: How long is a doubling time?
Unchecked, it seems to be ~3 to ~5 days. Rate of spread depends very much on human behavior, and details of how we interact.

Older people remember black-and-white movies in which a handkerchief in a suit-pocket (or a purse) was not only “fashionable” but (in most places) also a matter of state and local law, for several decades.

The Spanish Flu of 1918-1919 was a training excercise, compared to what we are now facing. Most the world is still in denial about how serious this is.