One vaccine for life: Lessons from immune ontogeny.

There remains a general misconception that the immune status of the fetus and neonate is immature or insufficient. However, emerging research in immune ontogeny prompts reconsideration of this orthodoxy, reframing this period instead as one of unique opportunity. Vaccine responses (qualitative and quantitative) vary between individuals, and across demographic cohorts. Elements of baseline immune status and function predict vaccine response - some of these factors are well described, others remain a subject of ongoing research, especially with the rapidly expanding field of 'omics' research, enabled by development of highly granular immune profiling techniques and increasing computational capacity. Age is one of the strongest predictive factors associated with variability in the response to vaccination; and predictable variation in response to vaccination is a key to identify the crucial underlying mechanisms. Specifically, circulating maternal antibody in the young infant can modulate immune response to vaccination, acting as an 'undercover adjuvant' that, counter to current dogma, may offer a pathway to longer lasting, higher quality immune response to vaccination. Exciting avenues for novel research in this area have the potential to dramatically alter how we protect the world's most vulnerable population - the very young.