whats the difference between efficacy and effectiveness?

[newmum35]

Whats the difference between "efficacy" and "effectiveness" in this? I'm so confused.

http://www.ncbi.nlm.nih.gov/sites/en...ubmed_RVDocSum

[PaigeC]

Great question!

Efficacy refers to whether the intervention can be successful when it is properly implemented under controlled conditions, whereas effectiveness refers to whether the intervention typically is successful in actual clinical practice

(from this unrelated) http://www.jointogether.org/news/you...ficacy-vs.html

[Sileree]

Pretty much it breaks down to:

efficacy = does it produce antibodies

effectiveness = does it prevent disease

So a vaccine may have a 95% efficacy level but it may also be much less effective against preventing the disease. Antibodies do not always mean immunity.