These conditions make the Pfizer vaccine result irrelevant to you

Once the vaccines roll out on a massive scale, our pace of learning will quicken, as the sheer numbers will reveal previously unknown, or unclear, issues. There are already a few cases that emerged from the U.K. that involved adverse reactions that are being investigated further. Some commentators believe that these people have conditions that would have excluded them from the Pfizer trial. What they mean is the Pfizer trial results don't apply to them, because anyone with those conditions were excluded from the experiment. (I wrote about exclusions here.)

Such exclusions are routine, and done for the safety of the excluded people. The flip side is those excluded types of people are more likely, perhaps much more likely, to experience adverse events, for that's why the researchers didn't want to include them - for ethical considerations.

There are a lot of exclusions in the Pfizer trial. The following is a full list. If any of these conditions apply to you, then you should know that the trial participants do not have these conditions, and thus the trial result may not apply to you (in terms of efficacy as well as safety results). Consult your doctor.

I have just copied these from the protocol, unaltered (The conditions that apply to the Phase 1 trial only are omitted.)

Note: Condition #2 referring to HIV status supposedly applies only to the Phase 1 and 2 trials but according to the FDA Briefing document, Pfizer only started enrolling HIV-positive people in the latter stage of the Phase 3 trial (this creates a situation in which the results we are seeing for this subgroup include few participants who meet the two-month-post-second-dose requirement.)

***

Medical Conditions:

1. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator’s judgment, make the participant inappropriate for the study.

2. Phases 1 and 2 only: Known infection with human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B virus (HBV).

3. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s).

4. Receipt of medications intended to prevent COVID-19.

5. Previous clinical (based on COVID-19 symptoms/signs alone, if a SARS-CoV-2 NAAT result was not available) or microbiological (based on COVID-19 symptoms/signs and a positive SARS-CoV-2 NAAT result) diagnosis of COVID-19.

8. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination.

10. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection.

11. Women who are pregnant or breastfeeding.

Prior/Concomitant Therapy:

12. Previous vaccination with any coronavirus vaccine.

13. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. If systemic corticosteroids have been administered short term (<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days before study intervention administration. Inhaled/nebulized (except for participants in Phase 1 – see exclusion criterion 14), intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted.

15. Receipt of blood/plasma products or immunoglobulin, from 60 days before study intervention administration or planned receipt throughout the study.

Prior/Concurrent Clinical Study Experience:

16. Participation in other studies involving study intervention within 28 days prior to study entry and/or during study participation.

17. Previous participation in other studies involving study intervention containing lipid nanoparticles.

Comments

[MVE]

Wow, so this reads as asserting here zero correlation between general human population and those matching 1+ of the list. That seems like the wrong prior.

[Kaiser]

MVE: That's certainly not what I intended so thanks for pointing this out. People who meet any of these criteria should consult their doctor before taking the vaccine. My prior is that the scientists at Pfizer believe there could be complications and that's why these subgroups were excluded. Because of the exclusion, we did not learn anything specific about these subgroups during the trial.

I think your argument is that the trial data should move the prior towards accepting the vaccine in aggregate and for any subgroup - I might be persuaded on the efficacy front but not on the safety front, because I'm concerned about the small sample size for any subgroup.

Nevertheless, for certain subgroups, such as pregnant women, we have an embedded natural experiment (though small) since some women in each group will have become pregnant by accident during the trial. So if we wait longer, there will be more data.
The FDA may have specific recommendations for certain excluded subgroups. That's why consulting with the doctor is the way to go.