This is how Ivermectin works.
It basically paralyzes invertebrates, in dosages that are not harmful to vertebrates.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7464486/

how often can you take ivermectin?

I took it once a day for 5 days, and it worked with the zinc, D and C .
I am not sure of recommended dose though.

In response marcelo acevedo to his Publication

Only people mentioned by @Sunny2021 in this post can reply

In response Sunny Star to her Publication

From Ivermectin.com
Dosage by body weight: