Infectious diseases remain a leading contributor to deaths among children under five worldwide—alongside preterm and intrapartum causes—with pneumonia, diarrhoea, and malaria accounting for a substantial share of under-five mortality. The burden is highly unequal: children in sub-Saharan Africa face markedly higher risks than those in high-income settings, and most global malaria deaths occur in the WHO African Region, predominantly among children under five. In Europe, respiratory syncytial virus (RSV) is a major reason for infant hospital admissions, with the heaviest burden in early infancy. These patterns underscore wide geographic heterogeneity in pathogen distribution and clinical impact.

In parallel, child nutrition is experiencing a “double burden”. While stunting and wasting persist in many low-resource contexts, overweight and obesity have risen sharply among school-age children and adolescents. Recent joint estimates from UNICEF/WHO/World Bank document slow progress on undernutrition alongside increasing childhood overweight, and WHO reports a pronounced global rise in overweight (including obesity) among 5–19-year-olds since the 1990s.
Nutrition and infection are biologically intertwined. Protein-energy malnutrition compromises immune development and function—including thymic integrity and T-cell-mediated responses—thereby heightening susceptibility to severe disease and sepsis. Conversely, obesity is characterised by chronic low-grade inflammation and altered adipose–immune crosstalk (for example, excess pro-inflammatory cytokines), which may amplify dysregulated host responses during and after infection.

Within countries, inequalities mirror these global divides. National surveys and cohort analyses from China, for example, show persistent rural disadvantages in linear growth alongside higher overweight/obesity in urban youth—though gaps are evolving over time as lifestyles and food environments change. Such heterogeneity highlights the need for integrated strategies that address both undernutrition and excess adiposity within local health systems.

This Special Issue will synthesise epidemiological evidence and mechanistic insights on how child nutritional status—spanning wasting, stunting, underweight, and overweight/obesity—shapes the risk and severity of infectious diseases. By assembling work from leading groups, we aim to inform policy and clinical practice with actionable, context-specific evidence to reduce severe infections, improve outcomes, and accelerate progress towards child-health-related SDGs.

We invite authors to submit original research, reviews, meta-analyses, and case reports on the following topics:

1. Epidemiology and Disease Burden of Child Nutritional Disorders
Global or regional trends in child malnutrition (wasting, stunting) and overweight/obesity, and their association with infectious diseases (e.g., pneumonia, diarrhoea, sepsis, malaria).

2. Biological Mechanisms Linking Nutritional Abnormalities to Infection Risk
Immune deficiencies caused by malnutrition (e.g., protein-energy deficiency), such as thymic atrophy and impaired T-cell function.
The impact of obesity-related chronic low-grade inflammation (e.g., adipose tissue macrophage infiltration, pro-inflammatory cytokine release) on infection susceptibility.
The role of gut microbiota dysbiosis in the relationship between nutritional abnormalities and infection risk.

3. Impact of Nutritional Status on Severe Infection Outcomes
Differences in severe disease progression, length of hospital stay, and mortality among malnourished or obese children with infections.
The influence of metabolic abnormalities (e.g., insulin resistance, dyslipidaemia) on the prognosis of sepsis, severe pneumonia, and other conditions.
Evaluation of nutritional interventions (e.g., micronutrient supplementation, dietary adjustments) in improving infection outcomes.

4. Nutrition and Infection in Special Populations
Nutrition and health outcomes in preterm/low-birth-weight infants (survival, mortality, quality of life, neurodevelopment, and other short- and long-term outcomes).
Characteristics of antibiotic-resistant infections in children with nutritional abnormalities.
The role of nutritional therapy in rare infectious diseases.

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Impact of Children's Nutritional Status on Adverse Infection Outcomes