If I have 2 apples. And you have 10 times as much.
Do you think you have 20 apples, or do you think you have n=2, n*2^(10) = 2048 apples?
As far as Iโm aware, 30 fold and 30 times are simply synonymous with eachother.
Other way around, if I have 2 apples and you have 10-fold more, is where I think it gets confusing. I think there are some limited scientific/mathematics contexts where n-fold refers to powers of 2 but that appears to differ from the colloquial meaning which is just a synonym for times.
I thought infectious diseases was one of those contexts, but I guess not.
The โfoldโ has its equal in the german โfachโ which means x*n of the n-fold. The โtimesโ is just a synonymous term that developed too.
I think you might get confused here, because it is usually used in the context of something having increased tenfold, which us often used to describe the result of an exponential growth. Nobody says โit increased twofoldโ. Outside of scientific topics, language doesnt really refer to exponential growth. As we saw with Covid, it is a concept difficult to grasp for people in general and it is not part of the day to day language.