Thread by @VPrasadMDMPH

Every time you add a dose of vax
from 1 to 2
2 to 3
3 to 4

you have some increased risk of myocarditis leading to hospitalization (for sure)

& possibly, some lower risk of being very sick with covid

How do we weigh these?
🧵

Of course good vaccine approvals occur when:

the reduction in risk of bad covid outcomes from getting 1 more dose is
> (Greater than)
the risk of bad vaccine outcomes from getting 1 more dose

This must be re-calculated with each dose

There is uncertainty around both estimates

We know the rate of myocarditis after dose 2 in these ages (1 in 5-10k), but not dose 3

We know the risk of hospitalization at these ages among unvaccinated

That risk falls with 1 dose; it falls a bit more with 2

How much more does the risk of bad covid outcomes fall with a 3rd dose?

is this greater than the risk of myocarditis leading to hospitalization with 3 rd dose?

Of course, the question is easy for an 85 year old!
But when you get to a 12 - 30 year old (particularly boy) its hard

Its hard because the risk to a vaccinated young person is already so low!

How much lower can it go!?

Myocarditis meanwhile has no theoretical ceiling.

The goal of vaccine regulation is to demand studies that can answer the question.

A large randomized trial is such a study.

Yes, they are costly, but Pfizer has plenty of funds

Yes, they require large sample size, but many in America are eager to enroll

No, they don't take as long as you think, when enrollment is brisk and you are worried the outcome will occur often.

Of course, that should be the regulatory standard

Remember: the top 2 FDA officials in Vax have resigned over booster pressure!

That is insane btw

What about the benefit for mild infections?

Consider that no number of doses will totally prevent you from having cold and flu symptoms at some point in the future

What about the benefit of boosting these ages on other age groups?

The answer is: that is not much of a consideration in regulatory science because it is TOO SPECULATORY

Remember all those people who modeled Covid spread and got it right...

Remember them?

Exactly

As long as it is so uncertain, the decision must be made solely on the basis of what is best for those actually getting the shot.

If the FDA takes this action it will be a total gamble

it won't be the first one.

But each of these gambles is dangerous.

If a future scientist -- one who isn't panicked by reading twitter -- performs a study that shows conclusively that some age (probably in the boy 12 to 30 range) got an extra dose of vax with a net harm profile

You will do serious damage to trust in vaccines for a generation.

That damage will be catastrophic.

The reason many of us have been writing on this issue for months is that this is a existential threat to vaccination programs.

medpagetoday.com/opinion/second…

If any additional dose in any age is net deleterious, you have a problem.

The top 2 FDA officials have resigned b/c they do not like these gambles.

As someone who has studied drug policy for a decade, neither do I

Follow @walidgellad for facts/ no spin