Note that views expressed in this opinion article are the writer’s personal views and not necessarily those of TrialSite.
Dr. Ron Brown
May 29, 2021
Dear Readers: Please forward the following information about COVID-19 mRNA vaccines to your U.S. Congressional representatives. Five critical questions are listed concerning vaccine efficacy. Your Congressional representatives should direct these questions to Dr. Anthony S. Fauci of the National Institute of Allergy and Infectious Diseases. The questions, along with suggested answers, are based on information from Medicina | Free Full-Text | Outcome Reporting Bias in COVID-19 mRNA Vaccine Clinical Trials (mdpi.com).
- What does vaccine efficacy mean in a COVID-19 mRNA vaccine clinical trial?
Vaccine efficacy, also known as the relative risk reduction, is a measure of how effective a vaccine is in reducing a COVID-19 infection under the strictly controlled experimental conditions of a randomized trial.
- What are the vaccine efficacy measures for the COVID-19 mRNA vaccines from Pfzier/BioNTech and Moderna?
The vaccine efficacy for the Pfzier/BioNTech vaccine is 95.1%, and the vaccine efficacy for the Moderna vaccine is 94.1%.
- In addition to vaccine efficacy, how is the vaccine absolute risk reduction calculated in a clinical trial?
The vaccine absolute risk reduction is calculated by subtracting the percentage of people who became infected in the trial’s vaccine group from the percentage of people who became infected in the trial’s placebo group.
- What are the absolute risk reduction measures for the COVID-19 mRNA vaccines from Pfzier/BioNTech and Moderna?
The absolute risk reduction for the Pfzier/BioNTech is 0.7%, and the absolute risk reduction for the Moderna vaccine is 1.1%.
- Why should both absolute and relative risk reduction measures from COVID-19 mRNA clinical trials be reported to the public?
Reporting relative risk reductions alone can cause misleading interpretations of vaccine efficacy. Absolute risk reduction measures provide more meaningful information for clinical and public health purposes, while relative risk reductions are more often used by researchers to compare results from different trials. FDA recommendations for communicating trial findings to the public include reporting both relative risk reduction and absolute risk reduction measures, which are equally important to meet legal and ethical obligations of informed consent for a treatment.
Ron B. Brown, School of Public Health and Health Systems, University of Waterloo, Waterloo, ON Canada