SPAMST:
The FDA document in question reads: “Among 3410 total cases of suspected but unconfirmed COVID-19 in the overall study population, 1594 occurred in the vaccine group vs. 1816 in the placebo group”.
If these cases were in fact all the genuine Covid-19 cases identified in the trial, this would indeed have demonstrated a 12% efficacy rate. However, the figures include some that were likely not positive and exclude some genuine cases.
The 12% claim relies on an incorrect interpretation of the meaning of “suspected but unconfirmed” Covid-19 cases, which the FDA briefing document also refers to as “suspected cases of symptomatic COVID-19 that were not PCR confirmed.”
It appears that Pfizer’s definition of a “suspected but unconfirmed” Covid-19 case was someone who experienced a Covid-19 symptom, but subsequently tested negative through a PCR test.
Therefore this data would include many cases that were not actually Covid-19 and exclude cases that were Covid-19 and confirmed by a PCR test.
It therefore can’t be used to calculate the vaccine’s efficacy against symptomatic Covid-19, which the trial was designed to measure.
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