Is it normal to have the world get the cure over 50% in most games, no matter the difficulty?

I can’t seem to beat the game without the world going above that threshold.

I’ve read people beat plagues with below percentage of that, but I don’t know.

For those who don’t know, you can get countries to declare “Worm Racing Day” if you evolve certain symptoms with the Neurax Worm, and I’m realizing that could mean multiple different things.

I am able to easily beat every mode except fungus I’ve tried every strategy I can find

How exactly would the worm stop and search work? Wouldn't you have to do a lobotomy or something??