Vaccines have "efficacy" (lab conditions) and "effectiveness" (real-world conditions) as two different metrics. Vaccine efficacy- % reduction in disease incide

Vaccines have "efficacy" (lab conditions) and "effectiveness" (real-world conditions) as two different metrics. Vaccine efficacy- % reduction in disease incidence in a vaccinated group compared to an unvaccinated group under optimal conditions (example: Randomized Control Trial). Vaccine effectiveness- ability of vaccine to prevent outcomes of interest in the “real world”. This short interview with a virologist is interesting for contrasting between different vaccines https://www.youtube.com/watch?v=d2KVKn0BvlM https://www.youtube.com/watch?v=d2KVKn0BvlM