10th Dec 2020, New England Journal of Medicine:
“Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine”
Non-cases (randomized) | Covid positive | |
| Vaccinated (dose 2 of BNT162b2) | 18.556 | 8 |
| Unvaccinated (dose 2 of Placebo) | 18.530 | 162 |
“BNT162b2 mRNA Covid-19 Vaccine conferred 95% protection against Covid-19 in persons 16 years of age or older.”
FDA Advisory Committee Meeting on
Pfizer-BioNTech COVID-19 Vaccine
December 10, 2020
Briefing Document (at pag 42)
“3,410 total cases of suspected but unconfermed Covid-19″
Should ever be mentioned these 3,410 cases in the paper?
“As specified in the protocol, suspected cases of symptomatic COVID-19 that were not PCR-confirmed were not recorded as adverse events unless… seriousness”
Should these suspected cases ever undergo for PCR follow up considering their potentialities of switching to Covid-19 positivity?
“…these data do not raise a concern that protocol-specified reporting of suspected but unconfirmed COVID-19 cases could have masked clinically significant adverse events that would not have otherwise been detected…”
Whereas all the suspected cases had been re-tested for Covid-19, would that have concerned safety or, rather, results?
CDC (Centers for Disease Control and Prevention)
E = Efficacy
In the Worst Theoretical Scenario…
Whereas Risk Ratios would include 3,410 suspected but unconfirmed Covid cases (100% false negative hypothesis)
Covid positive confirmed + suspected unconfirmed | Non-cases (n. of subjects who received 2nd dose) | Total | |
| Vaccinated | 8+1,594=1.602 | 18,556 | 20,158 |
| Unvaccinated | 162+1,816=1.868 | 18,530 | 20,508 |
| Total | 3,580 | 37,086 | 40,666 |
Risk of Covid among vaccinated group = 1,602/20,158 = 0.0794 = 7.9% (a)
Risk of Covid among unvaccinated group = 1,868/20,508 = 0.0910 = 9.1% (b)
Risk Ratio* = a/b = 0.0794/0.0919 = 0.86 (86%) indicating that subjects in the vaccinated group would approximately be 4/5 as likely to develop Covid as would subjects in the unvaccinated group.
*If all the suspected unconfirmed cases were included into the 2nd dose group, this would not affect the result, as shown below:
a = 1,602/18,556 = 0,086 and b = 1,868/18,530 = 0,1 a/b = 0,86 = 86%
…the vaccinated group would experience 13% fewer Covid cases than it would have if this group had not been vaccinated.
However, here reviewed the NEJM perspective
Covid pos tested | Non-cases (pt who received 2nd dose) | Total | |
| Vaccinated | 8 | 18,556 | 18,564 |
| Unvaccinated | 162 | 18,530 | 18,692 |
| Total | 170 | 37,086 | 37,256 |
Risk of Covid among vaccinated group = 8/18,564 = 0.00043 = 0.043%
Risk of Covid among unvaccinated people = 162/18,692 = 0.0086 = 0.86%
Risk Ratio = 0.00043/0.0086 = 0.05 (5%) indicating that subjects in the vaccinated group are approximately 1/20 as likely to develop Covid as are subjects in the unvaccinated group.
Vaccine Efficacy = 0.86-0.043/0.86 = 0.95 (95%)
Confirming a 95% efficacy: therefore consistent with a very high protection.
As expected in this case.
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″… We need the raw data…
Peter Doshi, BMJ, January 4, 2021
Further Bibliographic Resources
- https://blogs.bmj.com/bmj/2021/01/04/peter-doshi-pfizer-and-modernas-95-effective-vaccines-we-need-more-details-and-the-raw-data/
- https://wayback.archive-it.org/7993/20201217213133/https://www.fda.gov/advisory-committees/advisory-committee-calendar/vaccines-and-related-biological-products-advisory-committee-december-10-2020-meeting-announcement
- https://www.cdc.gov
- https://restoringtrials.org/2020/09/18/covid19trialprotocolandstudydocs/
Ronzinantes 