A search on Twitter for Pfizer currently shows many people talking about a supposed recent release of documentation (tens of thousands of pages) from Pfizer. A simple Internet search shows many personal blogs discussing the release, sites claiming to have the documents in question (I was unable to access them, and at any rate am not inclined to go through such a large document myself), and news articles debunking a claim about adverse effects.

In the Twitter discussion, I have noticed a few common themes: along with the usual anecdotes (that I see every time there is a swell in Twitter discussion of COVID vaccines) about individuals supposedly harmed by the vaccine and protest of Pfizer's profit margins, there are four distinct claims I have noticed:

  • A claim that the leak of the Roe v Wade decision was timed to distract from the contents of the Pfizer documents (this is, of course, an unprovable and irrelevant conspiracy theory, so I have not selected it as the topic here)

  • A claim that the documentation indicates over a thousand deaths caused by vaccines during the trials (the news coverage I can find all seems to focus on this claim, making the simple argument that these deaths cannot necessarily be attributed to the vaccine; that's good enough for me as it stands, so this is also not the claim I want to highlight. I suppose this is similar to the classic misuse of VAERS seen in many other covid-19 related questions.)

  • A claim that the vaccine was not recommended during pregnancy or lactation, as the studies did not determine whether the vaccine would be excreted in human milk. It was established later that the vaccine is passed on this way, but this has been deemed safe and beneficial, so this is also not the claim I find interesting for skeptics.SE purposes.


The preceding is largely meant to establish that the documents in question indeed exist and that they have been looked over, but that I don't know where to look for a thorough treatment of the topic. There is one claim outstanding in the discussion which I have not seen addressed. I will cite example Tweets here:


While the system kept you busy with abortion in USA & War in Ukraine,

Pfizer data came out after a court order.

The vaccine was 12% effective & dropped to less than 1%.

No trials were done on pregnant women before giving them!

Pfizer vax had a 0.83% chance to save you.



Pfizer data just out! We no why they fought to seal data for 75 years! Vaccine was 12% effective. Never trialled in pregnant women, tested on 7 Rats before it was given to them! Actual Pfizer vaccine had a 0.83% chance to save ur life from Covid. SHOCKED


Now that the "#Science" is out that the #Pfizer vax is actually 12% effective the first 7 days, and then below 1% after that time lapse... How do we fight the mandates legally? Even the kangaroo courts we have in #Canada won't be able to come up with enough bs to cover for that.

The numbers cited are consistent: it is claimed that Pfizer has now admitted their vaccine to be only "12% effective".

My question is: Where does this number come from, and does it have any salience or validity? How are the anti-vax crowd interpreting the document to infer such a result, and how could this happen with the same data that was used to produce headlines of over 90% efficacy at the time the vaccines were released? It seems as though outright fraud is being alleged.

  • 6
    A claim that the vaccine was not recommended during pregnancy or lactation, as the studies did not determine whether the vaccine would be excreted in human milk. It was established later that the vaccine is passed on this way - No. Absolutely this is not true. The antibodies your body produces as a result of having been vaccinated are passed on. The vaccine is not, and is rapidly cleared by your immune system. (Vaccines in general are highly recommended for pregnant women, and it is now standard of care to give Tdap early in the third trimester to maximize protection to the infant)
    – CJR
    May 4, 2022 at 18:38
  • 2
    No, thank you. Honestly, this question is a few twitter randos, a link to a duckduckgo search that changes for everyone who clicks on it, and your thoughts. If I was going to start editing, I would delete it.
    – CJR
    May 4, 2022 at 19:09
  • 1
    Is the tweet that talked about the war in Ukraine trying to claim that the war was started in order to hide this data?
    – Joe W
    May 4, 2022 at 19:26
  • 8
    The complaint isn't that this is a non-notable topic, but that you need to find a notable single source that's written down exactly what the claim is so that people can write specific responses. Do you really think that many people on twitter are all on the same page when it comes to what they're claiming? It's an internet telephone game, they're just repeating vaguely similar-sounding things until it loses meaning. If you want to know the basis for the claim, I suggest a search engine - this is a site to skeptically analyze if specific claims are correct, not go and find them for you.
    – CJR
    May 4, 2022 at 19:37
  • 3
    The Daily Mail article states more pertinently that the '12%' figure only relates to children between 5 and 11 and relates only to Omicron Covid-19.
    – Nigel J
    May 5, 2022 at 11:59

1 Answer 1


I'm not entirely sure when the documents were released, but Le Monde connects the twin claims (12% and 1%) of the first tweet in the question to the writings of Sonia Elijah, some of which you can read here, as found by Mad Scientist. Le Monde comments that

Pour arriver à ce « 12 % », Mme Elijah s’appuie sur un document, rendu public depuis au moins le 8 décembre 2020 : la notice d’information envoyée par Pfizer aux FDA, dans laquelle l’entreprise se targue des fameux 95 % d’efficacité du vaccin qui allait être autorisé. Une phrase y interpelle l’ancienne journaliste de la BBC : « Parmi les 3 410 cas totaux de Covid-19 suspectés mais non confirmés dans la population globale de l’étude, 1 594 sont survenus dans le groupe vacciné contre 1 816 dans le groupe placebo », écrit Pfizer.

Un calcul réalisé à partir d’individus… négatifs « Si vous calculez l’efficacité vaccinale à partir de ces chiffres, elle est incroyablement basse, 12 % », s’emporte Sonia Elijah. Sauf que contrairement à ce qu’elle présuppose, rien ne permet d’affirmer avec certitude que ces 3 410 personnes symptomatiques ont bien été malades du Covid-19. Certes, il n’est pas possible d’écarter une part de faux négatifs (des personnes contaminées, mais non détectées en raison d’un problème de réglage du test PCR, ou d’une charge virale trop basse, par exemple).

So, the Pfizer documents are from their Dec 2020 FDA submission, and Elijah derived the 12% efficacy figure by including all the participants who had some symptoms related to Covid-19, although they were not confirmed (e.g. PCR) as being infected with SARS-CoV-2.

  • I've seen related claims elsewhere. The anti-vaxxers are counting the people who had symptoms that the PCR test didn't confirm. Hey, that means it wasn't Covid--so no surprise it's about the same in the vaccine and control arms. Never mind that the real-world performance of the vaccine is similar to the counts of the PCR-confirmed cases in the trials, this data has been overtaken by reality and means nothing. May 12, 2022 at 3:00
  • @LorenPechtel, could you elaborate on the reality claim? From my govt (Israel) released daily data I see, that new confirmed cases in the last two months per 100 thousands are higher for vaccinated vs unvaccinated(I suppose these people are get called by names by you).
    – dEmigOd
    Jul 8, 2022 at 7:04
  • @dEmigOd What I said was overtaken by reality is that the real-world performance of the vaccine matched what we would expect if the "cases" not confirmed by PCR weren't relevant. As for what we are seeing now: the case numbers have ceased to mean much as home tests predominate. Confirmed cases are now strongly biased towards those who are seriously ill--being at high risk would make people more likely to get vaccinated and also more likely to get seriously ill. Jul 8, 2022 at 21:35
  • @LorenPechtel, while your claim could have some basis, the data is split by age cohorts and pretty consistent. So are you claiming that in each age cohort more vulnerable got vaccinated, while less did not? I may buy this in the 90+ group, but this is highly unplausible in the 12-18, 18-29 and other "younger" groups. It just can not be that there are so many vulnerable people in such young people groups.
    – dEmigOd
    Jul 9, 2022 at 4:45
  • @dEmigOd This is one of the ploys of the anti-vax crowd--pretending the number of people with pre-existing conditions is low. Jul 9, 2022 at 15:24

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