Before COVID, the largest, and growing, anti-vax base were those who thought vaccines caused autism in children. Post-COVID total vaccine "skepticism" became a shibboleth for an order of magnitude more people.

I watched a lot of people that I formerly thought were intelligent make the leap from "COVID vaccines are harmful" to "anything bad that has happened since vaccination became common place is the fault of vaccines". Usually it was just contained to believing vaccines cause autism, but everything under the sun is being blamed on vaccines right now, from people being fat, to allergies, cancer and excess deaths.

To answer your question, there was an undercurrent of anti-vax sentiment in the past, and now it's been mainstreamed and is even dumber than it ever was. I believe you're correct in your assumptions.