The COVID-19 mRNA vaccines authorized for use were found to be safe and effective in clinical trials and real-world conditions. A professor in Ireland baselessly claims in a video circulating on social media that they are not, and that those who get the vaccines will die as a result within several years.
Federal officials authorized two mRNA vaccines for COVID-19 after they were determined to be safe and effective against symptomatic illness in clinical trials. But a Texas doctor, in a widely shared video, falsely claims the vaccines don’t provide protection and that they’re actually “experimental gene therapy.”
Efficacy is a measure of how well a vaccine performs in a clinical trial. It specifically refers to a relative reduction in infection or disease when comparing the vaccinated group to the placebo (or control) group.
For instance, both the Pfizer/BioNTech and Moderna vaccines were primarily evaluated for their ability to prevent symptomatic COVID-19, with the former having a 95% efficacy and the latter having a 94% efficacy. This means your risk of getting sick is cut by 94% or more if you are vaccinated.
All of the authorized vaccines are effective at preventing symptomatic disease.
According to the results of the phase 3 trials, the Pfizer/BioNTech and Moderna vaccines had an efficacy of 94% or higher, which means your approximate risk of getting sick is cut by 94% or more if you are vaccinated. It’s important to keep in mind that the effectiveness of the vaccines outside the controlled setting of a clinical trial is typically somewhat lower.
Scientists don’t know how long protective effects of the vaccines will last, but clinical trials, which are continuing, are trying to determine the answer.
Dr. Peter Marks, the head of the FDA’s Center for Biologics Evaluation and Research, said in December that based on the experience of people who were immunized earliest in the trials, it appears that protection against the disease lasts at least several months.