Response to Argument Against COVID-19 Vaccine Absolute Risk Reductions

Response to Argument Against COVID-19 Vaccine Absolute Risk Reductions

Note that views expressed in this opinion article are the writer’s personal views and not necessarily those of TrialSite.

A commentary published on, April 29, 2021, claims that COVID-19 vaccine clinical trials were too brief to judge outcomes using absolute risk reductions (ARR), and that extending a clinical trial’s length of time can increase the ARR, thereby reducing the number needed to vaccinate to prevent one infection. Why Number Needed to Treat Can Be Misleading for Vaccines ( The author’s argument in the commentary may be technically correct under certain assumed conditions or considered “contextual points,” but the argument is clinically meaningless at best.

The Pfzier/BioNTech vaccine’s absolute risk reduction is 0.7%, and the vaccine efficacy or relative risk reduction (RRR) is 95.1% Medicina | Free Full-Text | Outcome Reporting Bias in COVID-19 mRNA Vaccine Clinical Trials ( Published results from the Pfzier/BioNTech phase 3 clinical trial covered the period from May 2020 to November 2020, having a trial length of 6-7 months; more than just “a few weeks” claimed by the commentary. Inside the Pfizer/BioNTech COVID...

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