The COVID presents as the flu, the symptoms are the same, so that means without a test there needs to be some other way to identify that a new virus is spreading.
The way to identify if a new virus is spreading is basically 3 ways:
Dramatic increase in cases:
In the U.S. for the last 20 years there has been a low of 9.3M cases and a high of 45M cases. China has had similar numbers, so in order to get someone's attention we'd need a ridiculous spike in cases in a very short time, and in October, November, and early December China did not have that ridiculous spike in cases. So they would not have known a new virus was circulating based on cases.
Different symptoms:
Covid presents as the flu, so there was no way to know that a new virus was circulating based on symptoms
Increased deaths:
In the U.S. for the last 20 years we've seen a range of 12,000 to 65,0000 deaths, a pretty wide range. China has seen similar numbers, so in order to get someone's attention we'd need to see a huge spike in deaths before it would get someone's attention, and again in October, November and early December China did not have a huge spike in deaths.
Basically the 3 ways to know something different is happening, didn't take place.
Which leads me to he most important question no one is asking, "How did China know they had a problem when there wasn't any data that would tell them something different was happening?"
This for me is the real question. IMHO the only way China was able to discover they had something different going on is because they had prior knowledge or information.
I don't think this was malicious, I think they were studying the virus in the lab, and a Jr. member of the team did something dumb or had an accident, and wanting to avoid getting into trouble the Jr. member of the team covered up what happened.
Then that Jr. member of the team got sick, and some other people they knew got sick, probably other members of the lab team and it was at his point Lab management knew they had a problem. This is how China knew they had a problem when only a handful of people are sick.