Have they been subject to medium to long term safety testing on humans?
Yes. For over two years now. Using a population of hundreds of millions of people and a control population of people who xerox misinformation and hand it out to strangers in grocery stores.
News flash: the vaccinated ones are doing way better.
As an addendum, the idea that a vaccine can produce side effects years down the line is a myth. A vaccine is a one-time payload - if any side effects are going to crop up, they will inevitably be in the few weeks following vaccination as your body processes it. After that, if nothing has gone awry, you're good.
I often think back and wonder about the 5G = COVID people on Twitter and r/conspiracy. Where are they now? Do they even feel in the slightest bit silly? Were they even real? So very many questions.
As an addendum addendum, I have some news for people worried about long-term effects of encountering only the spike proteins: you're really going to hate the long-term effects from taking that virus raw.
Did billions of people end up getting the mRNA vaccine? I thought the traditional vaccine was more widely deployed outside the United States.
In any case, the objection is nonsense. On populations this large, the number of side effects was slightly less than might have been expected at the outset. The researchers did good work.
For vaccines in general, yes. But kooky people that think this is some kind of trick are worried about it being an mRNA vaccine, which is indeed somewhat new. The idea has been around for about fifty years, but the first human clinical trials were only about a decade ago and COVID was the first large-scale human deployment.
Now, in fairness, they were almost entirely ready at the time. I would imagine, without COVID, we probably would've still seen mRNA vaccines become mainstream already, though maybe last year or this year instead of in 2021. But COVID stepped up the final stages of approval significantly.