Factors influencing innate immunity and vaccine responses in infancy

Area of Science:

• Immunology
• Pediatrics
• Public Health

Background:

• Neonatal mortality remains a significant global health challenge, despite progress in child survival.
• Infections are a leading cause of infant deaths, highlighting the need for effective prevention strategies.
• Early life immune development (immune ontogeny) is crucial for long-term health and vaccine efficacy.

Purpose of the Study:

• To explain the heterogeneity in vaccine responses observed in young children.
• To explore the impact of host, pathogen, and environmental factors on infant immune responses.
• To underscore the importance of early life interventions for preventing infant mortality.

Main Methods:

• This is a review article, synthesizing current knowledge on immune ontogeny and vaccine responses.
• It examines factors influencing the immune system's development and response to interventions.
• Examples are used to illustrate the interplay of various factors shaping immune responses.

Main Results:

• Vaccine responses in infants are highly variable due to complex interactions.
• Host factors (genetics), pathogen characteristics, and environmental exposures significantly influence immune training.
• Interventions like vaccination and nutrition can "train" the infant immune system, impacting disease susceptibility.

Conclusions:

• Understanding the "immune interactome" in early life is critical for improving infant health outcomes.
• Targeted interventions, informed by knowledge of immune ontogeny, can reduce infant mortality, particularly from infections.
• Further research into early life immune development is essential for optimizing public health strategies.