Dictionary of Cancer Terms
View in Spanish: Atenuado
Attenuated
Weakened or thinned. Attenuated strains of disease-causing bacteria and viruses are often used as vaccines. The weakened strains are used as vaccines because they stimulate a protective immune response while causing no disease or only mild disease in the person receiving the vaccine.
Source: National Cancer Institute Dictionary of Cancer Terms, available at www.cancer.gov/dictionary.