Strain with weakened or reduced virulence.
Inactivated, rendered harmless (e.g., killed viruses used to make a vaccine). Some of the ways in which viruses and other pathogens may be attenuated are by heat, chemical, or radiation treatment.
Alive but debilitated; an attenuated microorganism has lost its ability to cause disease.
Attenuated refers to microorganisms that have undergone treatment to diminish their capacity to cause disease. These attenuated organisms are utilized in certain vaccines. By reducing the virulence or pathogenicity of the microorganisms, they can stimulate an immune response in the body without causing severe illness. Attenuated vaccines play a crucial role in providing immunity against various infectious diseases while minimizing the risk of adverse effects.