Baseline immune states (BIS) associated with vaccine responsiveness and factors that shape the BIS. Semin Immunol. 2023;70:101842
Semin Immunol. 2023;70:101842
This review was made possible by the generous financial support of the National Institute of Allergy and Infectious Diseases (NIAID) under award number R01 AI142086 (to D.U.) and U01 AI165452 (to D.U.). Opinions, interpretations, conclusions, and rec- ommendations are solely the responsibility of the authors and do not necessarily represent the official views of the National Institute of Al- lergy and Infectious Diseases (NIAID).
Vaccines are among the greatest inventions in medicine, leading to the elimination or control of numerous diseases, including smallpox, polio, measles, rubella, and, most recently, COVID-19. Yet, the effectiveness of vaccines varies among individuals. In fact, while some recipients mount a robust response to vaccination that protects them from the disease, others fail to respond. Multiple clinical and epidemiological factors contribute to this heterogeneity in responsiveness. Systems immunology studies fueled by advances in single-cell biology have been instrumental in uncovering pre-vaccination immune cell types and genomic features (i.e., the baseline immune state, BIS) that have been associated with vaccine responsiveness. Here, we review clinical factors that shape the BIS, and the characteristics of the BIS associated with responsiveness to frequently studied vaccines (i.e., influenza, COVID-19, bacterial pneumonia, malaria). Finally, we discuss potential strategies to enhance vaccine responsiveness in high-risk groups, focusing specifically on older adults.