What do vaccine efficacy numbers actually mean?

Efficacy is a crucial concept in vaccine trials, but it ’s also a tricky one. If a vaccine has an efficacy of, say, 95%, that doesn’t mean that 5% of people who receive that vaccine will get COVID-19. And just because one vaccine ends up with a higher efficacy estimate than another in trials doesn’t necessarily mean it’s superior.
Source: The Economic Times Healthcare and Biotech News - Category: Pharmaceuticals Source Type: news