This is not too much to ask in my opinion. COVID 19 is lethal in some cases and life-threatening why would anyone wanna bet on how many will get infected with Covid. Basically, people who bet on high numbers will pray that more people will be infected just for them to win money. This is not an ethical type of bet that should be made.
I have not seen or read if there is a report like that but a credible gambling site will not implement something like this, they will not compromise their ethics for money, only low level gambling sites will do something like this, they cannot compete with big gambling sites so they create something that will generate controversy and interest, but I won't go for bets like this.
I don't think they only want to generate controversy as you say. This disease has consequences all over the world, it's not insignificant. Creating bets on its spreading could be a tool predict its evolution.