That would essentially be a "robot with a little timer". And it's just the only one a layman like myself can come up with off the cuff. I have to assume there are more.
Edit: I watched the video, and this guy is presumably much smarter than I am, so I wouldn't be surprised if I'm missing something, but it doesn't seem very convincing.
He's basically just claiming what you said, that conditions that take an extended amount of time to manifest just dont exist. That in some portion of the population, those conditions will necessarily manifest quickly. The video doesnt explain why I should believe that other than saying something like "these things are possible, but very unlikely".
If you don't want to go down this path, though, know that it probably will just take that breadth of experience to develop the understanding and intuition necessary to be able to say and explain things on the subject with confidence.
You should believe it because you trust people like the one in the video when they tell you it's a good idea to clean your wounds to prevent infection. You vaguely understand this has something to do with germs, but you (probably) don't know all about the various actual diseases that cause open wound infections, their outcomes, their treatments, the history of research behind it, etc. It's an entire field of medicine, actually. Luckily for you, a lot of the important stuff can be condensed into a single important general-action for the populations: clean your wound with soap and water, then, cover it with a bandage.
So why do you trust domain experts when they tell you about first aid, and not what they tell you about hugely more complex subjects, such as vaccinations and drug trials?
Why the sudden skepticism now? During a pandemic, of all times? If this was a movie, the climax / resolution would be the development of a vaccine - thank god, the experts delivered us from this terror. What were you expecting instead? 10 years of lockdown while we wait for things to shake out?
But even so, I was expecting to watch the video and have it explain why I should believe x, and instead I found it just reiterating that I should believe x.
This is a little off topic for the thread (I was originally just responding to the claim that "Vaccines don’t have long term side effects"), but based on what you said:
Would you feel the same way about "you should clean your wounds to prevent infection" as you would with "you should inject this compound that we invented 1 (or 2 or 3) years ago?