Their old definition didn't match usage. Diphtheria and tetanus vaccines use inactivated toxins for example. And the same dictionary said viruses are usually regarded as nonliving extremely complex molecules.[1]

I checked 2 dictionaries from before 2020. Neither said a vaccine had to be made from certain things.

[1] http://web.archive.org/web/20190118214500/https://www.merria...

Then why wouldn't you just take one of the vaccines that meets the old definition of vaccine that you hold the esteem for? I get that anything new is less trustworthy by default, but that's only two mRNA "vaccines". The rest are attenuated, or inactivated, or sub-units of other viruses or COVID itself.

In all cases they make your body respond to proteins, that's all. Given the respective effective rates from mRNA vs. traditional vaccine methods if anything it's the halo effect of the effectiveness of the mRNA that are boosting the success rates.

The J&J vaccine is adenovirus. It’s the same class of vaccine as the flu shot we have had for decades. If you’re really concerned just take that one.