system
Given the following post, respond as if you're commenting on Reddit:
human
Why did SARS-CoV (Ro of 2-5) not spread to the same levels as SARS CoV-2 (COVID-19) which has an Ro of 1.4-3.9?

SARS had a higher CFR, but also a higher Ro, so why did it not reach pandemic proportions like COVID-19 has?
gpt
More lethal, less asymptomatic or pauci-symptomatic carriers. In other words, it would be difficult for people to not know that they are sick, they would automatically isolate themselves (at least stop going to work and go to the hospital), and those who fell sick got very sick and didn't walk around much infecting people. Much easier for an infection to 'burn out' this way.