mRNA has been studied since the 1980s. In 1990, researchers at the University of Wisconsin managed to make an mRNA vaccine which worked in mice. So the mRNA technology is not all that new. For example, google "Katalin Karikó".
What was lacking was funding to develop mRNA beyond academic research. DJT drove the necessary funding through operation warp speed.
The Pfizer/Biotech phase 3 trial involved 43,661 volunteers. The Moderna Phase 3 trial involved 25,654 volunteers. Since then 165 million people in the US have received the full dose of the vaccine (either Pfizer, or Moderna).
Historically, any long term effects from vaccines is known within about 8 weeks after the start of mass vaccinations. We are well past that point.
This is not really specifically due to the mRNA vaccine. According to 42 U.S. Code § 300aa–22, enacted in 1986, "No vaccine manufacturer shall be liable in a civil action for damages arising from a vaccine-related injury or death associated with the administration of a vaccine after October 1, 1988, if the injury or death resulted from side effects that were unavoidable even though the vaccine was properly prepared and was accompanied by proper directions and warnings."
https://www.law.cornell.edu/uscode/text/42/300aa-22
Needless to say, 1986 is well before the covid vaccine so this is a bit of fear mongering.
Coronaviruses are known for undergoing rapid mutations. As such, the science will keep changing as new mutations develop.
I'm sure there are a great many things that have been extensively researched since the 80's and even before, that we still know very little to nothing about. Simply because something has been researched in a laboratory setting does not mean everything is known about it.
The common cold is a coronavirus. We are not, nor have we ever been terrified of it mutating into a different strain. Covid may be more deadly, but even it has a 99.99% survival rate for the un-vaccinated.
We can't know long term implications of the vaccine when we are still figuring out the short term implications of them. They still aren't even positive how long they will last in most people. They started off saying if you get the vaccine you won't get covid. Then that moved to well, you'll get it, but you won't transmit it to others, then on to well, you can get it, and transmit it, but your chances of living through it move from 99.999 to 99.9999 percent.
From polio vaccines being released with live virus, to measles vaccines resulting in kids getting measles, RSV vaccines resulting in enhanced versions of the virus, Dengue fever vaccine as recently as 2017 resulting in a more sever form of it, 2009 H1N1 vaccine causing narcolepsy in some, and the glass in the HPV vaccine, vaccines obviously have a chance at going wrong.
Vaccines have save countless lives, probably numbering in the tens of millions. Nobody is saying vaccines don't have a place or that they shouldn't exist. Some are simply saying that whether or not to take that vaccine should be a choice they make, not one that is made for them.
Judges giving sentencing for X hours of community service OR get the vaccine, states running vaccine lotteries, the Biden administration pushing for the federal government and private employers to make life as insufferable as possible for those that won't get it, these are all things that push me in the never ever will I get that shot camp.
That is my opinion and my opinion only. I sincerely hope that everyone that wants the vaccine gets it as quickly as possible without even having to stand in line. Heck, Biden will even send someone directly to your door.