Vaccine-induced immune responses are heterogeneous.

Heterogeneity of vaccine-induced immunity is the result of genetic and environmental factors.

Age is a major determinant of vaccine efficacy, with poorer responses with increasing age.

Individuals with type 2 diabetes mellitus have impaired responses to vaccination.

Vaccines induce quantitively and qualitatively different effector responses between populations but also between individuals within populations. Several factors are known to affect the success of vaccination, including age, gender, co-infections (e.g. HIV), pre-existing inflammatory status and co-morbidities such as type 2 diabetes mellitus (T2DM). These factors, either alone or in combination, strongly influence vaccine induced immunity and thereby possibly vaccine efficacy. Vaccination strategies should therefore not only be evaluated in young, healthy selected individuals but also in individuals with immune ageing, persisting inflammation and co-morbidities, and include the measurement of qualitative rather than only quantitative measures of vaccine effects.

Vaccination

Infectious diseases

Type 2 diabetes mellitus

Heterogeneity

Inflammation

Immune response

© 2025 The Author. Published by Elsevier Ltd.