William C. Campbell delivered his Nobel Lecture on 7 December 2015 at Aula Medica, Karolinska Institutet in Stockholm. It is well worth listening to, even though it is over 30 minutes long.
Ivermectin is now out of patent for many years, so there are no new studies funded by the medical establishment. While it is given to nearly all refugees from the Middle East, Africa and Latin America, there is no money to make in giving it as a prophylactic and cure for COVUD-19, even though there are multiple studies that it is effective.
The evidence since April is even more positive, yet there is no decision from CDC to approve its use for COVID, rather the opposite.