It matters a lot if ivermectin doesn't do anything to stop C19, even if it is otherwise safe (it surely is, dosed professionally). People take ivermectin instead of vaccinating or complying with NPIs. If ivermectin doesn't work, that is a very, very big deal.
But it seems almost certain to me that at least some people feel safe thanks to taking ivermectin (while distrusting mainstream vaccines), and those people would turn eventually to the vaccines if those were the only perceived path towards C19 safety.
Perhaps on the margin some would, but I suspect most would fall into the "natural immunity" camp.
So in my mind, we need to weigh the damage done by blocking safe ivermectin use for some number of people to the damage done by a much-smaller number of people remaining unvaccinated when they otherwise would get the jab.
Seems like it could go either way depending on your specific assumptions.
One doesn't imply the other, but it is certainly happening. People are using (being led to use) ivermectin as a prophylactic against covid, an alternative to the vaccine.
