Agreed. Though not all last a year, and the COVID trials had large numbers of volunteers.
I defer to someone that works in the industry to say whether vaccine trials last longer than regular medicine (e.g. Parkinsons or Alzheimers drugs).
But I suspect that vaccines need less time for trials because vaccines are made using standardised processes that are tweaked to produce the expected responses, vs. novel drugs that have never been synthesized before.
This one [0] in the UK famously went wrong: "The German company that developed the drug hoped it would revolutionise treatment of leukaemia and rheumatoid arthritis.
But within minutes of having the drug administered, all of the test subjects began feeling unwell."
0. https://www.bbc.co.uk/news/magazine-35766627#:~:text=When%20....
"Long term" side effects mean weeks or few month later, not years as many people assume. In the past things like rare autoimmune disease associated with vaccination appeared within weeks after the dose, but it may take years to pick up the statistical signal, which may explain this belief. There is literally no reason to assume the mRNA vaccines will cause side effects 5 years later or something.
> Trials often last a year or more and involve several thousand patients.
Also this seems to be a US/UK difference, as over here phase 3 includes long-term safety before it's approved for use, with emergency use authorization to skip that being the exception: https://coronavirus.jhu.edu/vaccines/timeline