There is no indication whatsoever that MMR has likely long-term health effects, and there are indications that C19 could have long-term health effects, and what we appear to learn month by month is more alarming, not less, with respect to the question of whether or not C19 is a "you either die of it in a month or you're fine" situation.

It also doesn't have to be a universal effect for it to generate effectively universal concern among parents. If it turned out that 1/20 kids suffered permanent kidney damage due to infection, most parents would keep their kids home. Look at the stats on school shootings and note that we pointlessly traumatize kids to assuage the concerns of parents. That's your figure of merit: that's how powerful the long-term C19 effect would need to be to change the behavior of the median parent.

I agree with these (hopefully not incorrectly) restated things I think you believe:

* It is more likely that MMR has few significant long-term health effects than if COVID-19 does

* COVID-19 effects are unlikely to be binary outcome

* Effects need not be universal for them to affect parental behaviour

However, none of that agreement is important to the discussion I was hoping to have. My comment was solely on the epistemology. I suspect you also use the same methods I was talking about in my previous comment.

If that is the case, then perhaps some other day we can argue about what the priors are. If we're good about it, we'll end up with the Aumann Agreement Theorem (+ corollaries) result, and rapidly agree (through likely both of us shifting our priors as we exchange information).

I think we have no disagreement and am happy to conclude this here.

Just to give you one possible side effect: sterility. There are plenty of viruses that when caught as a child do not give much in terms of symptoms but will make you sterile for life. That's not something that will come out in the next two months.

True, and whether MMR 2 will kill you or your mind in 60 years isn't something that comes out in 42 years. We don't know that yet.

But if I had to guess, you're probably pro-MMR-2 (as am I), so the question is what epistemology permits that view?

It could, but we have a lot of data on those diseases and typically a weakened or reduced dose live virus shot has a known outcome with some outliers where the shot leads to the disease or something worse in the relatively short term.

For COVID-19 we are still guessing at most of this, hopefully the long term effects are not too bad and those effects of contracting the disease will get reduced over time.

But I would definitely not rule out some shocker long term effect at this stage that we are unaware of, especially not when taking into account developing organisms such as children, where effects can stay hidden for a long time.

I think we're close to agreement, but not quite. We're not, after all, guessing at most. For instance, it's pretty unlikely that COVID-19 will cause you to grow three extra feet from your nose within the next 60 years.

There are some things we don't have high certainty on, but our epistemology would be faulty if we ignored how other coronaviruses behave, just like it would be faulty if we ignored how other attenuated viruses behave when we examine if MMR-2 will cause instadeath at age 60.

But there are quite a few examples of some pretty nasty effects that only show up when a person reaches maturity. So better to take this the slow and the sure way, more evidence is better.