As we enter flu season and the bottom of immune people was back in October, I'm pretty sure immunity is going to go out the window.

I'm also 90% sure that they sell negative Covid tests in China off Baidu or one of the other shops, it's why that plane in Milan had 50% positive cases. They don't DNA test Covid tests for flights, lol.

Edit: It's just a really bad time for positive cases to fly around right now.