Newborn susceptibility to infection vs. disease depends on complex in vivo interactions of host and pathogen

Area of Science:

• Immunology
• Pediatrics
• Infectious Diseases

Background:

• Newborn infectious disease poses the highest burden across the human lifespan.
• The exact causes of this vulnerability remain unclear.
• Traditional views suggest lower host immune responses in newborns compared to adults.

Purpose of the Study:

• To review evidence on newborn immune responses to infection.
• To propose a paradigm shift in understanding newborn infectious disease.
• To highlight implications for reducing infant mortality and suffering.

Main Methods:

• Review of in vitro and in vivo experimental data.
• Synthesis of existing evidence on host immune responses.
• Analysis of the relationship between infection and infectious disease.

Main Results:

• In vitro data suggest lower newborn immune responses.
• In vivo data reveal exuberant newborn immune and inflammatory responses to infection.
• Host response, not infection itself, often causes disease in newborns.

Conclusions:

• The newborn immune system exhibits a dual response to infection: potentially lower in some aspects but exuberant in others.
• Understanding the host response is critical for explaining increased clinical suffering in early life.
• This paradigm shift has significant implications for developing effective interventions against newborn infectious diseases.