[eagsalazar2]

Maybe it is less about it being the 2nd or 3rd shot and more about how recently you received your last shot? I got my 2nd shot 7 months ago and we've already heard that protection fades over time, so maybe the booster just works because it boosts, not because it is really any different than my 2nd shot.

[SideburnsOfDoom]

> Maybe is ... about how recently you received your last shot .. not because it is really any different than my 2nd shot.

No. That appears not be the situation. Immunity shortly after the thirds shot is substantially higher than shortly after the second

https://twitter.com/PaulMainwood/status/1460191035531878405

https://twitter.com/PaulMainwood/status/1458026852249919490

[eightysixfour]

I have seen speculation that the second dose was given too quickly.

[SideburnsOfDoom]

Firstly, YMMV, different people got different separations of different vaccines. The US doing Pfizer 3 weeks apart was the fastest. The UK gave out AZ and Pfizer. First at a 12 week interval, then shortened to 8 weeks

The question is: too quickly for what? My understanding is that

a) If the goal was optimal immunity in the longer term then yes, it might be overly quick.

b) But if the goal was fighting the raging pandemic that needed urgent actions right now as "the house is on fire", and you have a lot of vaccine doses, then no, maybe not too fast.

Finally, a lot of vaccine courses require more than 2 doses, separated by more than a couple of months. UK standard childhood vaccination schedule for instance. "Polio" is in there 5 times. Polio is a memory, but only because because to this day they don't mess around with vaccinating against it

[eightysixfour]

Agreed, I was only referencing a.

[wlesieutre]

I wonder if that's a factor in the Pfizer/BioNTech vs Moderna performance. Moderna had a higher dosage, but it was also 4 weeks between doses instead of 3.

[SideburnsOfDoom]

> but it was also 4 weeks between doses instead of 3.

YMMV. The UK gave out AZ and Pfizer. First at a 12 week interval, then shortened to 8 weeks.

[Symmetry]

If you assume an unlimited supply of vaccine then the shorter dose interval gets everybody to good level of sterilizing immunity as quickly as possible.

[SideburnsOfDoom]

Yep. if you need to fight against a raging pandemic, then quickly as possible (as quickly as is tested to be safe, quickly as makes a significant difference) is the over-riding concern.

[astrange]

That implies we thought about it in the US, but we didn't really, and our public health people seem to be completely inflexible about everything. The schedule we used for vaccines is just what was done for their trials.

[SideburnsOfDoom]

> The schedule we used for vaccines is just what was done for their trials.

There is a reason for that - what's being deployed is what has been tested. You could work out an optimal schedule, but that might take years of trials, and meanwhile people are dying.

[xchaotic]

Given how quickly the virus mutates, giving it less frequently makes even less sense.

[eightysixfour]

My response was with respect to maximizing immuno response following vaccination. There is some evidence that larger spacing between doses increases response.