I am currently watching a video, that, from how far I've gotten into it, has been about how various "vaccines," such as for diseases like the flu, pneumonia, measles, and whooping cough (amongst other[s]), had no effect on their mortality rates. The guy presenting the claims, Roman Bystrianyk, was making some pretty logical and statistics-based claims, and someone told me that I shouldn't trust him, because he's not a doctor or "virologist", and because doctors and "virologists" have studied this topic more, so they must be more correct than him. He asserted that he didn't study this topic enough, because he doesn't have the credentials. Wow! Someone is wrong because they don't have "truth credentials!" That's an example of the argumentum ad hominem fallacy. Also, it should be noted that the only basis this person dismissed the guy's claims is because of this, and he didn't even know what the claims were! On account of the actual claims not being refuted, they still stand.
Anyway, no evidence has been presented that the only people who are knowledgeable enough (to make claims about) about "viruses" and "vaccines" are doctors and "virologists." What if all these credentialed people are wrong? What if they are all biased and are basing their views on previous people with no evidence and because of already assuming the conclusions to be true?
This argument also commits the appeal to authority fallacy, because it cites supposed authorities and credentialed figures instead of an actual argument. One could say that because Wikipedia (and some other sites) say that this fallacy does not include appeals to the "scientific [which pre-assumes that the consensus is based on studies which comport with the scientific method] consenus." That would actualy also be an example of the fallacy! Just because people who've written on Wikipedia and other websites say something about whether or not something is fallacious, that doesn't mean that they're right! If something is fallacious, it means, I think, that it can be used to support incorrect conclusions and multiple contradictory conclusions. It is conceivable, in a hypothetical reality, that all the "scientists" (which, again, pre-assumes that their claims have been verified by studies using the scientific method) could agree that "viruses" don't cause disease. Would the claim then be right? Someone might say, "Well, it is NOT actually conceivable that all the scientists could be wrong." But I see no evidence for that. So, it's just more baseless speculation...
So, in conclusion, this dude (Roman Bystrianyk) still seems to be correct, whilst the more credentailed folk are not.