A vaccine is assessed by its efficacy; the extent to which it reduces risk of disease under controlled conditions, and its effectiveness, the observed reduction in risk after the vaccine is put into use.
Vaksin dinilai dari khasiatnya; Sejauh mana dapat mengurangi risiko penyakit dalam kondisi terkendali, dan keefektifannya, pengurangan risiko diamati setelah vaksin mulai digunakan.