What Does Vaccine’s ‘Efficacy Rate’ Mean?

The Covid-19 vaccines manufactured by Pfizer/BioNTech and Moderna both showed very high “efficacy rates,” of around 92-95%. The Johnson & Johnson vaccine, on the other hand, has a considerably lower efficacy rate: just 66%. Does that make the first two vaccines better or more desirable? According to public health experts, the answer is no. This video explains why these numbers are not relevant to understanding which vaccine is the best one, and why comparing efficacy rates can be misleading.