Peer-reviewed article
Trained Immunity in Childhood Vaccination
ChenRongRong Cai, Lubnaa Hossenbaccus, Eva Kaufmann ·
Summary
Written by AI, not yet AICS's view · claude-sonnet-5-5This is a review article on how some childhood vaccines may protect through 'trained immunity', a form of memory in the body's first-line (innate) immune cells. It covers the features of newborn and infant immunity and the evidence for this effect from live vaccines such as BCG, measles-containing vaccines and oral polio vaccine. It also discusses how innate and adaptive immune memory interact. The authors suggest this idea could help design vaccines with broader protection and may offer options for non-infectious childhood diseases such as cancer and allergies.
Key points
- Conventional vaccine design targets antigens that produce lasting T and B cell memory.
- Live vaccines (BCG, measles-containing, oral polio) are reported to protect through trained immunity, a metabolically and epigenetically mediated memory in innate immune cells and their progenitors.
- Trained immunity is especially relevant in early life, when adaptive immune responses are limited and innate immunity is the main defence.
- Trained immunity may broaden protection against severe infections and improve vaccine efficacy.
- It may offer therapeutic opportunities for non-infectious paediatric diseases, including cancer and allergic disorders.
Limitations
The abstract describes a narrative review and gives no data, effect sizes or study methods, so it cannot show how strong the evidence is. It is not tied to a specific country or programme, and the Canada hint is not confirmed in the text.
Abstract
Conventionally, vaccine design has focused on identifying antigens that induce durable T and B cell memory and provide long term protection against subsequent encounters with the same pathogen. Unconventionally, a growing number of epidemiological, preclinical, and clinical studies demonstrate that live vaccines, including Bacillus Calmette Guérin (BCG), measles-containing vaccines, and oral polio vaccine, induce protection through trained immunity, a form of metabolically and epigenetically mediated memory in innate immune cells and their progenitors. This concept is particularly relevant during early life, when adaptive immune responses are constrained and innate immunity represents the principal line of host defence. In this review, we discuss the unique characteristics of neonatal and infant immunity, summarize current evidence for trained immunity induced by childhood vaccines, and describe the bidirectional interplay between innate and adaptive immune memory. We further highlight the potential of trained immunity to broaden protection against severe infections, improve vaccine efficacy, and provide therapeutic opportunities for non-infectious paediatric diseases, including cancer and allergic disorders. Harnessing trained immunity represents a conceptual shift in paediatric vaccinology and may guide the development of next generation vaccines that provide broader and more resilient protection during the period of greatest immunological vulnerability.