You could replace the phrase “face masks” with “shrimp gumbo” and that sentence would still be 100% accurate. If all you can tell me about masks is that, combined with other measures, they can slow the spread of COVID-19—that’s not very compelling! Give me a number! Quantify the effectiveness of mask wearing by itself! If you tell me masks reduce my odds of getting COVID by 50%, then of course I’ll wear a mask. But if it’s only 0.05% then maybe I won’t bother. Numbers matter.
But quantitative data alone isn’t enough—good medical communication is also exhaustive. By “exhaustive” I mean that it includes all research on a given topic. Exhaustive communication bolsters your argument (“look at all this data!”) and helps undermine counterarguments (“we know about the conflicting data, but here’s why it doesn’t matter”).
At first glance, this BBC article appears to thoroughly debunk the use of Ivermectin for treating COVID-19. It says that of the 26 “major” Ivermectin trials, one third have statistical errors or indications of fraud, and the other two thirds don’t support the use of Ivermectin.