FWIW, COVID vaccines that use the "traditional" LAV/IAV technologies have been in development. My understanding is that they have been slower in development and have been less effective in trials than the Pfizer/Moderna/J&J type vaccines. I think a couple of examples of these would be COVI-VAC and Sinovac. The former is supposedly effective, but is still in trials and the latter is much less effective and (I think) developed by China.Oh yeah, one more thing. If the leading authorities primary and only concern was getting as many as possible vaccinated so that we might reach herd immunity, please help me understand why they wouldn't simply develop a third vaccine option based off of the classic, tried and true technology used to produce the Polio, Measles, Smallpox vaccines???
They should have anticipated that the late adopters, (i.e. those who never guinea-pig new drugs or technology until it's been debugged), would have reservations. However, almost all of that crowd has taken every other vaccine, so if you develop a COVID vaxx based on that technology, they'd take it in a heartbeat and we'd likely be well into the 90%+. It's such an obvious and easy fix, that them not doing it likely speaks volumes about their true agenda.
Even though I think there are and almost certainly will be no issues with the vaccines that have been distributed in the U.S., it is a good idea if they can get one of these type vaccines to market and approved by the FDA. For people who are hesitant, even if the hesitancy is unwarranted, it just makes sense to make available something they can feel comfortable with that gets them vaxxed. I also think it would have been better if the authorities had given better public explanations for why the vaccines that are readily available were better choices and why the others were not yet available. Anything that would have given the public good reason to trust authorities who have instead (IMO) shown that they are not trustworthy would have been a good thing.
All that said, I don't see anybody taking the mRNA (or J&J) vaccines as in any way guinea pigging anything. @Stumpfan has been correct in his repeated assertions that these vaccines are miracles. They are amazingly effective and safe and there is little reason to believe that there will be any long term issues with them.