Discerning, cautious people are being confused with the antivax crowd (like the Orthodox Jewish community in NY who still spread measles, they really don't take ANY vaccines). The Americans who didn't get the Covid vaccine did so because it was untested (as well as its reported serious side effects) and it is now proving to be ineffective, as well (the CDC advocating three shots in a year is the very definition of ineffectiveness when it comes to vaccines).

In addition to mRNA previously never working in ANY human application EVER due to unwanted immunogenic side effects, there has NEVER been a vaccine that worked for ANY human coronavirus EVER.
About 30 peer reviewed papers here, substantiating this:
https://archive.4plebs.org/pol/thread/357160531/#357179284

Remember that SARS2 (aka Covid19) is just SARS with an additional engineered furin site, and remember that MERS, also a Coronavirus, really did kill 34% of its hosts, so researchers have really tried for almost two decades to make a vaccine for human coronaviruses, BUT THEY ALL FAILED.

>there has NEVER been a vaccine that worked for ANY human coronavirus EVER
>there has NEVER been a vaccine that worked for ANY human coronavirus EVER
>there has NEVER been a vaccine that worked for ANY human coronavirus EVER