Welcome to DU! The truly grassroots left-of-center political community where regular people, not algorithms, drive the discussions and set the standards. Join the community: Create a free account Support DU (and get rid of ads!): Become a Star Member All Forums Issue Forums Culture Forums Alliance Forums Region Forums Support Forums Help & Search
5 replies = new reply since forum marked as read
Highlight: NoneDon't highlight anything 5 newestHighlight 5 most recent replies
Change urged to single vaccine dosing for Pfizer. Moderna not sure about South African variant (Original Post) steve2470 Feb 2021 OP
Thanks for updating your title n/t Yonnie3 Feb 2021 #1
This is potentially awesome, but probably nothing at all. Pobeka Feb 2021 #2
I agree with your last paragraph. Blue_true Feb 2021 #3
I checked -- the Pfizer phase III trial was only 2 doses, or a placebo Pobeka Feb 2021 #4
I have to agree with your assessment. Why recommend two doses if Blue_true Feb 2021 #5

Pobeka

(4,999 posts)
2. This is potentially awesome, but probably nothing at all.
Thu Feb 18, 2021, 07:48 PM
Feb 2021

I don't claim to understand the Pfizer protocols, but

a) If everyone got the two doses in the trials, and the dose spacing was 3-4 weeks, then what the article is claiming is that in the final 1 or 2 week period after the first dose, only 5% of the vaccinated individuals got symptoms. It would not give any way to assess efficacy beyond that 1 or 2 week period, because individuals got a second dose after a total period of 3-4 weeks, and there is no long term data to support an efficacy estimate for a single dose.

b) If some of the individuals in the trials only got a single dose, then this could be valid.

My guess if there was a second test group that only got one dose, Pfizer would already know the answer about the long term efficacy of a single dose and we'd have started with the one dose regimen.

Blue_true

(31,261 posts)
3. I agree with your last paragraph.
Thu Feb 18, 2021, 07:56 PM
Feb 2021

Pfizer must have developed the one dose data from recently vaccinated people. And like you, I am trying to figure out what “after 2 weeks mean”, does that mean a person is good against SARS-COV-2 for as long as the people that get two doses, or does it mean that once the vaccine kicks in 2 weeks, a person is good for an as yet undetermined time?

Pobeka

(4,999 posts)
4. I checked -- the Pfizer phase III trial was only 2 doses, or a placebo
Thu Feb 18, 2021, 08:27 PM
Feb 2021

There is no long term 1 dose study.

Answers the question.

https://pfe-pfizercom-d8-prod.s3.amazonaws.com/2020-11/C4591001_Clinical_Protocol_Nov2020.pdf

Caveat -- I haven't read the whole thing, but it appears that the phase I trial may have attempted to get some estimates from 1 dose (no -- see edit below), in subsequent phase 2/3 trials they only used 2 doses, which I assume means they learned 2 doses were required to get sufficient immunity.

on edit: -- even phase 1 protocol was 2 doses, according to the pdf referenced.

Blue_true

(31,261 posts)
5. I have to agree with your assessment. Why recommend two doses if
Thu Feb 18, 2021, 08:30 PM
Feb 2021

they had compelling data showing that one dose did the job.

Latest Discussions»General Discussion»Change urged to single va...