Efikasi

Efikasi refers to the extent a treatment, intervention, or preventive measure produces the intended health benefit under ideal or controlled conditions. In pharmacology and clinical research, efikasi is assessed mainly through randomized controlled trials designed to maximize internal validity. It is quantified using endpoints such as disease incidence, symptom change, or biomarker responses, and expressed as relative risk reduction or risk ratio; absolute measures like absolute risk reduction and the number needed to treat provide context.

Vaccine efficacy is estimated by comparing disease rates in vaccinated versus unvaccinated groups, typically reported as a percentage reduction in disease incidence. In pharmaceuticals, labeled efficacy denotes the maximal effect achieved under trial conditions, assuming adequate adherence and monitoring.

Efikasi is distinct from effectiveness, which describes how well an intervention performs in routine practice outside the controlled setting of trials. Trials assessing effectiveness may include pragmatic designs and broader patient populations and are more subject to real-world factors such as adherence, access to care, and concomitant therapies. Efficacy estimates can be influenced by study design choices, such as intention-to-treat versus per-protocol analyses, and by the chosen endpoints.

Regulatory agencies rely on demonstrated efikasi to approve products, while health technology assessments consider efficacy together with safety, cost, and real-world effectiveness to inform policy and reimbursement decisions. Limitations of efikasi data include limited generalizability, short follow-up, and potential publication bias.