Pfizer recently announced that its covid vaccine was more than 90 percent “effective” at preventing covid-19. Shortly after this announcement, Moderna announced that its covid vaccine was 94.5 percent “effective” at preventing covid-19. Unlike the flu vaccine, which is one shot, both covid vaccines require two shots given three to four weeks apart.
Based on Gilbert Berdine, a more meaningful measure of efficacy would be:[1]
Based on Gilbert Berdine, a more meaningful measure of efficacy would be:[1]
The number to vaccinate to prevent one hospitalization or one death.
However, those numbers are not available on either report.
What was reported?
- Have a treatment group that received the vaccine and a control group that did not.
- All the trial subjects were covid negative prior to the start of the trial.
- The analysis for both trials was performed when a target number of “cases” were reached.
- “Cases” were defined by positive polymerase chain reaction (PCR) testing.
- There was no information about:
- The cycle number for the PCR tests
- Whether the “cases” had symptoms or not
- Hospitalizations or deaths
- How long any protective benefit from the vaccine would persist
- Safety
- The “efficacy” figures quoted in these announcements are odds ratios as shown below:
| Pfizer Trial | Moderna Trial | |
| No of Participants | 43,538 | 30,000 |
| Total "cases"
found at the time of analysis | 164 | 95 |
| Cases in the Control Group | less than 0.7 % (or ~150 out of 21,750) | 0.6% (or 95/15,000) |
| Cases in the Treatment Group | one-tenth of 0.7% | about
one-twentieth of 0.6 % (or 5/15,000) |
Conclusions
There is no evidence, yet, that the vaccine prevented any hospitalizations or any deaths:
The Moderna announcement claimed that eleven cases in the control group were “severe” disease, but “severe” was not defined. If there were any hospitalizations or deaths in either group, the public has not been told. When the risks of an event are small, odds ratios can be misleading about absolute risk.
The publicists working for pharmaceutical companies are very smart people. If there were a reduction in mortality from these vaccines, that information would be in the first paragraph of the announcement.
Let's hope for the best. But, be cautious in the meantime before more evidences are presented and proved. Here are other articles for your perusal and stay safe:
- Here Are All The Things That Could Still Go Wrong With A COVID-19 Vaccine
- Oxford/AstraZeneca vaccine to undergo new global trial
- AstraZeneca Covid vaccine study results clouded by manufacturing error
- Dutch Study Involves Exposing Hundreds Of People To COVID-19 To Test Effectiveness Of Vaccines
- These Are The Best (And Worst) Places To Live During The Coronavirus Era
- How Does an mRNA Vaccine Work?
- "Life Won't Ever Be Completely Normal Again" - Renowned Infection/Immunity Expert Warns COVID Is Not Going Away
References
- What the Covid Vaccine Hype Fails to Mention (11/24/2020)
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