Covid-19 Vaccine Efficacy | Could It Be Due to Chance?

Covid-19 Vaccine Efficacy | Could It Be Due to Chance?

Covid-19 vaccine efficacy is on the top of everyone’s mind. Pfizer and BioNTech are moving along with FDA approval and showing upwards of 95% vaccine efficacy, Moderna is under way as well with 94.5% efficacy, and now Oxford and AstraZeneca seem to also be gaining some traction. In a previous video I explained what those incredibly high efficacy numbers mean, and in this video I’m going to help build on that intuition by walking through the intuitive answer to the number one question I received in response to that last video: how can we conclude much when the number of infected individuals in the vaccine trials was so low? For the Pfizer trial, at least for the preliminary data, only 94 people out of nearly 39 thousand were infected with Covid and yet everyone around the world was celebrating the trial’s results. For the Moderna trial, only 95 people out of about 30 thousand were infected with the same basic conclusion.

So how is it that with only 90 or so people infected out of 30 THOUSAND we can be so sure that the vaccine actually works? Welcome to Data Demystified. I’m Jeff Galak and in this episode I’m going to go through the intuition for why even seemingly small sample sizes like this can often tell us a whole lot. If you stick around, I’ll quickly go over the results of the vaccine trials and then work to build your intuition for why even with 90 or so infections out of tens of thousands of research participants, we should feel confident that the results of these trials are actually very strong evidence in support of the efficacy of these various vaccines.

Video explaining how to interpret Covid-19 Efficacy:

Video explaining statistical significance:

Video explaining randomized experiments:

Learn more about who I am and why I'm doing this here:

Video that explains how to adjust for inflation:

Follow me at:

Equipment Used for Filming:
Nikon D7100:
Yeti Microphone:
iPad for Teleprompter:
Camtasia for Video Editing:
Show More