> if they say something like "I need a minimum of 20 years before I'll trust a vaccine" they'll sound paranoid, which they are
Chronic lead poisoning, mesothelioma (cancer usually caused by abestos), lung cancer (cigarettes), various types of cancer caused by Agent Orange, and cancers caused by DDT take years-to-decades to manifest. Asking for 20 years is completely reasonable and supported by a dozen other substances that do have long-term side effects on that timescale.
> Also their timespan is almost certainly long enough that any pandemic would be long over by the time they'd trust it, essentially precluding vaccines as tool during a pandemic if everyone were to adopt their perspective.
Almost everyone that I've heard (except for a lone hardcore anti-vaxxer) who has expressed unease at the safety of the mRNA technology in general, not the specific application of it to SARS-CoV-2 - which is understandable, as there's no long-term trial data available about it. Several said that they were waiting to take the Novavax vaccine, which uses an older technology (subunit) that has been in use for decades.
So, assuming that the majority of people uneasy about taking the vaccine adopt that stance above, then no, there's no "precluding vaccines as tool during a pandemic" because the criteria is whether a particular vaccine technology has been tested for decades or not, not the particular payload.
> By virtue of its distribution these vaccines have already been tested far more extensively than any other vaccine in history at the time of their release. If you don't trust this vaccine then you should never trust any future vaccine.
Testing a vaccine with one million people for one year does not translate into ten years of study for one hundred thousand people. You cannot predict long-term effects with short-term data, and long-term effects are what these people are worried about. Nobody except hardline anti-vaxxers (who make up a tiny tiny minority of the population that I'm not discussing here) wants every single payload+technology combination to be tested for decades before use.
> Well my wife and I trusted the actual data instead of internet speculation, as well as the data showing what COVID can potentially do to fetuses, and we got pregnant well after both being fully vaccinated.
I'm reminded of a line from a sibling comment: "you get 0 applause from me if you randomly guess a “what if” correctly" - and without actual data as to whether mRNA vaccines have any long-term side effects (which is the issue under discussion), you're just guessing.
Finally, I'll preempt one of your talking points "We don't know what the long-term side effects of covid are either, yet, so why not pick the less risky of the two?" Because that is a personal choice - so it's up to the individual, not the government to impose.
It's generally a good strategy that, given ambiguous information, you still make the best use of what you have and pick the least risky option (i.e. vaccines) - however, in the specific case of vaccines in the US, the fact that the US government has shielded vaccine manufactures from legal liability means that there's significant downside in case there are long-term side effects.
If you want more people to take the vaccine, you should be campaigning hard to get that law repealed. I don't see anyone railing against anti-vaxxers doing that, so the more likely explanation is that these people are merely using the vaccine as an attempt to increase government control.