I interpret this as the comment saying "we won't know how this affected things until decades from now." Which can likely be attributed to existing vaccine skepticism and is unlikely to result in them changing their opinion in the next ever.

What I think a lot of people who are anti-vax miss is the risk of the vaccine compared to the risk of COVID. They feel like they're being asked something risky in a vacuum, when in fact, they're being asked for something with (as best as we can tell) limited risk against a backdrop of a dangerous virus that killed millions and caused a global pandemic.

Even if they could demonstrably prove the vaccine created a higher risk of outcomes for people who took it, the risk compared to getting COVID is de minimus, and the likelihood of getting COVID is high. I would be surprised if there was a significant population of people who had avoided it at this point.