Respiratory Infections in Young Children

Respiratory tract infections (RTIs) remain one of the most common causes of illness and death in young children, despite advances in vaccination and health programs. In children under five years of age, RTIs cause significant morbidity, social costs, and long-term health consequences. The clinical spectrum of RTI ranges from mild upper infections to severe lower respiratory tract infections (LRTIs) such as bronchiolitis and pneumonia. Viruses are the leading cause, especially in the first two years of life. However, in Latin America, there is limited information about how often RTIs occur, what viruses or bacteria are responsible, and how severe these infections are in community settings. Most existing data come from hospitalized cases, which underestimate the real disease burden. To address this gap, researchers launched the MINERVAL study, a multicenter, prospective birth cohort conducted in Cali, Colombia, and Panamá City, Panamá. The study began in May 2024 and follows children from birth to five years of age to better understand the epidemiology, etiology, and consequences of RTIs. A total of 436 newborns have been enrolled as of February 2025. This population-based cohort is followed by active surveillance twice a week using a phone app or calls, with in-person visits during RTI episodes and routine visits every six months in the first two years of life. From ages two to five, children continue follow-up every six months to assess long-term outcomes. The study has four main objectives: (1) to determine the incidence, etiology, and seasonality of RTIs in children aged 0-2 years; (2) to assess the pathogen-specific burden of infections caused by viruses such as RSV, hMPV, influenza, SARS-CoV-2, and others across outpatient and inpatient settings; (3) to evaluate long-term respiratory sequelae of LRTIs during early life and their association with chronic respiratory illness by age five; and (4) to analyze viral-bacterial interactions, focusing on how pneumococcal bacterial loads and immune responses influence disease progression. Preliminary data from 436 participants show 222 RTI episodes, including 42 LRTIs. The cumulative incidence of RTI was 40% at 100 days and 64.8% at 250 days. For LRTIs, incidence was 8.9% at 100 days and 12.2% at 250 days. Among LRTIs, 82.9% were mild, 14.6% moderate, and 2.4% severe. More than half of LRTI episodes required hospitalization, and 14.3% required intensive care. Samples have been collected from 91% of episodes for laboratory analysis. These findings confirm the feasibility of long-term active surveillance in this cohort and the high frequency of early-life respiratory infections. The continued study will provide critical insights into the incidence, mechanisms, and long-term health consequences of RTIs in Latin American children, supporting the development of new preventive and therapeutic strategies.