What is the leading cause of death in children under 5?

Pneumonia is the Leading Cause of Death in Children Under 5 Years of Age

Pneumonia is the single greatest cause of death in children worldwide, responsible for approximately 700,000 to 900,000 childhood deaths annually and representing 16-20% of all deaths in children under 5 years of age. 1

Epidemiology and Global Impact

The burden of pneumonia mortality is substantial and disproportionately affects certain regions:

• Annually, pneumonia causes approximately 700,000-900,000 childhood deaths worldwide 1
• In 2016, pneumonia was responsible for 13-16% of all deaths in children under 5 years 1
• Approximately 155 million cases of pneumonia occur in children every year worldwide 1
• 15 countries account for 70% of all pneumonia deaths: Afghanistan, Angola, Bangladesh, Chad, China, Democratic Republic of the Congo, Ethiopia, India, Indonesia, Niger, Nigeria, Pakistan, Somalia, Sudan, and Tanzania 1, 2

Age-Related Patterns

The impact of pneumonia varies significantly by age:

• 81% of pneumonia deaths occur in the first 24 months of life 1
• Mortality attributed to pneumonia decreases rapidly with age:
  • 67% of all deaths at 6 months
  • 14% at 18 months
  • Plateaus at 6% between 30-54 months of age 1, 2
• Incidence decreases more gradually with age:
  • 39% at 6 months
  • 22% at 18 months
  • 19% at 30 months
  • 13% at 42 months
  • 7% at 54 months 1

Risk Factors for Pneumonia

Several key risk factors contribute to pneumonia incidence and mortality:

• Household air pollution (population attributable fraction of 52%) 1, 2
• Lack of exclusive breastfeeding 3
• Undernutrition and malnutrition 3, 4
• Low birth weight 3
• Crowding 3
• Lack of immunization 3
• Clinical rickets 4
• Anemia (hemoglobin <10 g/dl) 4

Causative Pathogens

The main pathogens associated with childhood pneumonia include:

• Streptococcus pneumoniae (most common bacterial cause) 3, 1
• Haemophilus influenzae 3, 1
• Respiratory syncytial virus (most common viral cause, especially in younger children) 1, 3
• Mycoplasma pneumoniae (more common in school-aged children) 1

Prevention Strategies

Effective prevention strategies can significantly reduce pneumonia incidence and mortality:

• Immunization with vaccines for bacterial pathogens:
  • Streptococcus pneumoniae
  • Haemophilus influenzae type b
  • Pertussis 1
• Annual influenza vaccination for all children 6 months and older 1
• Immunization of parents and caregivers of infants <6 months with influenza and pertussis vaccines 1
• Immune prophylaxis with RSV-specific monoclonal antibody for high-risk infants 1
• Improvements in socioeconomic status, child nutrition, and HIV control 1, 2

Clinical Considerations

Healthcare providers should be aware of:

• The highest risk period is in the first 24 months of life, with particular attention needed for infants under 6 months 1, 4
• Case fatality rates are highest in children with:
  • Severe malnutrition (weight-for-age less than 60%)
  • Clinical rickets
  • Anemia (hemoglobin <10 g/dl)
  • Cyanosis
  • Heart failure 4
• Pulse oximetry screening should be routine and performed at the earliest point in the patient care pathway 1

Pitfalls and Caveats

Important considerations for clinicians:

• Resolution of radiographic findings may lag behind clinical improvement, so follow-up imaging is not routinely needed 1
• Imaging is not specific for the causative organism and plays a limited role in uncomplicated pneumonia 1
• Children with chest indrawing pneumonia and signs of severe respiratory distress, oxygen saturation <93%, moderate malnutrition, or unknown HIV status in endemic areas require close monitoring or referral 1
• Despite the availability of effective vaccines, many children who die from influenza-related complications have not been immunized 1

By understanding the epidemiology, risk factors, and prevention strategies for pneumonia in children under 5 years, healthcare providers can better target interventions to reduce this leading cause of childhood mortality.