Nonadjuvanted

Nonadjuvanted refers to vaccines or other immunogenic formulations that do not contain an adjuvant. An adjuvant is a substance added to some vaccines to enhance the immune response to the introduced antigen, potentially allowing lower antigen doses, fewer injections, or improved protection in particular populations. Nonadjuvanted vaccines rely on the intrinsic immunogenicity of the antigen, the vaccine platform, and the use of stabilizers or preservatives rather than additional immune stimulants.

In practice, many traditional vaccines are nonadjuvanted. Live attenuated vaccines such as measles, mumps, and rubella (MMR) and varicella are generally produced without adjuvants because their replication in the body provides sufficient immune stimulation. Some inactivated vaccines are also nonadjuvanted, though others use aluminum-based or other adjuvants to boost immunogenicity, especially when antigen content is limited or when enhanced responders are needed in certain populations (for example, older adults).

Nonadjuvanted formulations can have advantages, including lower risk of adjuvant-related local or systemic adverse events and simpler regulatory considerations. However, they may require higher antigen doses or repeat dosing to achieve comparable immunity, and may be less effective in populations with weaker immune responses.

In vaccine development and labeling, the term nonadjuvanted is used to indicate that no adjuvant is included in that specific formulation. The choice between adjuvanted and nonadjuvanted vaccines is determined by factors such as the target population, immunogenicity of the antigen, manufacturing considerations, and safety profiles.