Global, Regional, and National Burden of Lower Respiratory Infections in Children: A Systematic Analysis for the Global Burden of Disease Study, 2021.

Background: Lower respiratory infections (LRI) are a leading cause of death among children aged 0 to 14 globally. LRI burden estimates remain incomplete, especially in resource-limited settings.

Objective: To assess the global, regional, and national burden of LRI in children, analyse trends in incidence, mortality, and disability-adjusted life-years (DALYs), and predict future burden projections from 2022 to 2035, exploring variations in major bacterial pathogens.

Methods: This study utilises data from the 2021 Global Burden of Disease Study to analyse child LRI burden across 204 countries and regions. It assesses incidence, mortality, and DALYs, employing refined methods and forecasting future burdens using the Bayesian Age-Period-Cohort (BAPC) model, while examining variations in major bacterial pathogens affecting children's health.

Results: From 1990 to 2021, global child LRI incidence declined from 144.6 million infections to 69.9 million (estimated annual percentage change [EAPC] -2.4). Deaths fell from 2,033,975 to 1,271,013, with a mortality rate decline from 117 to 27.1 per 100,000 (EAPC -4.0). DALYs decreased from 180.7 million to 48.4 million, with the rate dropping from 10,389.6 to 2403.9 per 100,000 (EAPC -4.0). Western sub-Saharan Africa and South Asia reported the highest burdens, while East Asia showed the most reductions. Low- and middle-income countries faced greater burdens than high-income nations. Streptococcus pneumoniae remained the leading cause of LRI-related deaths in 2021. Projections indicate a further marked decline in child LRI deaths and age-standardised mortality rates globally by 2035, with under five mortality rates expected to remain the highest.

Conclusions: Despite reductions in LRI burden, it continues to threaten child health, particularly in resource-limited settings. Effective public health interventions and vaccination efforts are essential, with future research needed on evolving trends of bacterial pathogens to enhance child health outcomes.