@bubu12
bubu12 : la mortalité n’est pas le critère de jugement principal
et n’est même pas dans les critères de jugement secondaires.
“Suspected covid-19”
All attention has focused on the dramatic efficacy results :
Pfizer reported 170 PCR confirmed covid-19 cases, split 8 to 162 between
vaccine and placebo groups. But these numbers were dwarfed by a category of
disease called “suspected covid-19”—those with symptomatic covid-19 that were
not PCR confirmed. According to FDA’s report on Pfizer’s vaccine, there were
“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.”
With 20 times more suspected than confirmed cases, this
category of disease cannot be ignored simply because there was no positive PCR
test result. Indeed this makes it all the more urgent to understand. A rough
estimate of vaccine efficacy against developing covid-19 symptoms, with or
without a positive PCR test result, would be a relative risk reduction of 19%
(see footnote)—far below the 50% effectiveness threshold for authorization set
by regulators. Even after removing cases occurring within 7 days of vaccination
(409 on Pfizer’s vaccine vs. 287 on placebo), which should include the majority
of symptoms due to short-term vaccine reactogenicity, vaccine efficacy remains
low : 29% (see footnote).
If many or most of these suspected cases were in people who
had a false negative PCR test result, this would dramatically decrease vaccine
efficacy. But considering that influenza-like illnesses have always had myriad
causes—rhinoviruses, influenza viruses, other coronaviruses, adenoviruses,
respiratory syncytial virus, etc.—some or many of the suspected covid-19 cases
may be due to a different causative agent.
But why should etiology matter ? If those experiencing
“suspected covid-19” had essentially the same clinical course as confirmed
covid-19, then “suspected plus confirmed covid-19” may be a more clinically
meaningful endpoint than just confirmed covid-19.
However, if confirmed covid-19 is on average more severe
than suspected covid-19, we must still keep in mind that at the end of the day,
it is not average clinical severity that matters, it’s the incidence of severe
disease that affects hospital admissions. With 20 times more suspected covid-19
than confirmed covid-19, and trials not designed to assess whether the vaccines
can interrupt viral transmission, an analysis of severe disease irrespective of
etiologic agent—namely, rates of hospitalizations, ICU cases, and deaths
amongst trial participants—seems warranted, and is the only way to assess the
vaccines’ real ability to take the edge off the pandemic.
There is a clear need for data to answer these questions,
but Pfizer’s 92-page report didn’t mention the 3410 “suspected covid-19” cases.
Nor did its publication in the New England Journal of Medicine. Nor did any of
the reports on Moderna’s vaccine. The only source that appears to have reported
it is FDA’s review of Pfizer’s vaccine.