What is the most common cause of infectious mortality worldwide?

From the Guidelines

Lower respiratory tract infections, particularly pneumonia, are the most common cause of infectious mortality worldwide, accounting for approximately 2.6 million deaths annually. The burden of these infections is particularly heavy in low and middle-income countries and among vulnerable populations such as young children, the elderly, and those with compromised immune systems. According to a study published in 2019 1, pneumonia causes approximately 700,000 to 900,000 childhood deaths worldwide each year, with the majority of these deaths occurring in the first 24 months of life. The primary pathogens responsible for lower respiratory tract infections include Streptococcus pneumoniae, Haemophilus influenzae, respiratory syncytial virus (RSV), and influenza viruses.

Some key points to consider in the management and prevention of lower respiratory tract infections include:

• Prevention strategies such as vaccination (pneumococcal and influenza vaccines) 1
• Improved sanitation and reducing indoor air pollution
• Appropriate antibiotic use for bacterial infections
• Treatment typically involves antibiotics for bacterial pneumonia, supportive care including oxygen therapy when needed, and management of complications

It's worth noting that the high mortality rate from lower respiratory tract infections is often due to delayed diagnosis, limited access to healthcare, antimicrobial resistance, and underlying health conditions that complicate recovery. A study published in 2021 1 highlights the importance of appropriate antibiotic use and the need to consider the etiology of pneumonia in guiding treatment. Another study from 2025 1 emphasizes the burden of RSV infection in adults worldwide, including in Portugal, and the need for effective prevention and treatment strategies.

Overall, the management of lower respiratory tract infections requires a comprehensive approach that includes prevention, timely diagnosis, and appropriate treatment, as well as addressing the underlying social and economic determinants of health that contribute to the burden of these infections.

From the Research

Causes of Infectious Mortality

• The most common cause of infectious mortality worldwide is lower respiratory infections, particularly pneumonia, which is a leading cause of morbidity and mortality globally 2, 3, 4, 5.
• Streptococcus pneumoniae is the leading cause of lower respiratory infection morbidity and mortality globally, contributing to more deaths than all other aetiologies combined in 2016 4.
• Other common causes of infectious mortality include bloodstream infections, peritoneal and intra-abdominal infections, and infections caused by other bacterial pathogens such as Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa 6.

Global Burden of Infectious Diseases

• Lower respiratory infections are responsible for a substantial proportion of global deaths, with an estimated 2.4 million deaths in 2016 4.
• The global burden of infectious diseases varies by location and age, with the highest burden in sub-Saharan Africa and the lowest in high-income countries 6.
• Childhood wasting, household air pollution, and ambient particulate matter pollution are significant risk factors for lower respiratory infection mortality, particularly among children under 5 years old 4.

Prevention and Control Measures

• Vaccination is an effective way to prevent pneumonia and other infectious diseases, with the pneumococcal conjugate vaccine (PCV) being a significant protection for children and elderly adults 3, 6.
• Improved infection prevention, optimized use of antibiotics, and enhanced capacity for microbiological analysis are also crucial strategies for addressing the burden of bacterial infections 6.