I don't take a doctrinaire stance on ivermectin one way or the other. It may well be the case that taking a course of ivermectin, as suggested by these doctors, is preferable to taking the new vaccines, the long term effects of which are anyone's guess.

As for scientific studies, this may be of help: https://covid19criticalcare.com/wp-content/uploads/2020/11/FLCCC-Ivermectin-in-the-prophylaxis-and-treatment-of-COVID-19.pdf

Good luck!