![](https://assets.weforum.org/article/image/pCzqFPcwjdHjVeBO3tyAbeVzyPxJvJsdO80H5wyW_rk.jpg)
Health and Healthcare Systems
What’s the difference between COVID-19 vaccine efficacy and effectiveness?
Both 'efficacy' and 'effectiveness' represent the percentage of reduction in symptomatic infection among people who are vaccinated, in terms of COVID-19, but there's a difference.