RSV: the virus that overwhelms infants

By Ana Espino | Published on March 3rd, 2026 | 3 min read


Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infection in infants and young children worldwide. Nearly all children are infected before the age of two, but clinical severity varies widely depending on age, immune status, and comorbidities. In infants under six months, RSV is the leading cause of hospitalization for bronchiolitis.  

Globally, RSV causes millions of respiratory infection episodes each year, with several million hospitalizations and a non-negligible mortality burden, especially in low-resource countries. In high-income countries, its impact mainly manifests as seasonal surges that overwhelm pediatric emergency departments and intensive care units.  

From a pathophysiological standpoint, RSV infects the respiratory epithelium, triggering inflammation, cell necrosis, edema, and mucus hypersecretion. In infants, the small diameter of bronchioles predisposes to airway obstruction and hypoxemia. Beyond the acute episode, some data suggest an association between severe early RSV infection and later development of recurrent wheeze or asthma.  

Despite this substantial burden, management remains largely symptomatic, with no widely used specific antiviral in routine practice. Until recently, prevention strategies were largely limited to targeted immunoprophylaxis in high-risk infants.  

In this context, the 2025 consensus review analyzes RSV epidemiology, pathophysiological mechanisms, risk factors for severe disease, and new pediatric prevention strategies, highlighting recent advances that could transform RSV care.  

Which children are truly at risk?  

This work synthesizes global epidemiological data and recent progress in prevention. RSV accounts for most bronchiolitis cases in infants and is a frequent cause of hospitalization during winter seasonal peaks.  

Transmission occurs mainly through respiratory droplets and direct contact, with high contagiousness in both community and hospital settings. The virus infects the respiratory epithelium, inducing inflammation, cellular necrosis, and mucus hypersecretion. In infants, narrow airways promote obstruction and hypoxemia.  

Risk factors for severe disease include prematurity, bronchopulmonary dysplasia, congenital heart disease, immunosuppression, and exposure to secondhand smoke. Symptoms include rhinorrhea, cough, wheezing, tachypnea, and signs of increased work of breathing.  

Care remains primarily supportive, including oxygen therapy and hydration. Specific antivirals are rarely used in routine practice. For prevention, the monoclonal antibody palivizumab is recommended for high-risk infants, but its cost limits broad use. New strategies are emerging, including long-acting monoclonal antibodies and maternal vaccines designed to protect infants from birth.  

Toward a new era against RSV  

RSV remains a major cause of respiratory hospitalization in infants, with a strong seasonal impact on health systems. Its severity—particularly in children under six months and those with comorbidities—makes it a priority issue in pediatrics.  

This review aimed to update knowledge on RSV epidemiology, pathophysiology, and prevention strategies. The data confirm that, despite predominantly symptomatic management, morbidity remains substantial and largely predictable in at-risk populations.   

Current limitations include the lack of a widely accessible curative antiviral and heterogeneous prophylaxis strategies across countries. However, recent advances mark a decisive turning point. The development of long-acting monoclonal antibodies and maternal vaccines opens the door to broader protection during the first months of life.  

Ultimately, integrating these strategies into public health policies could significantly reduce hospitalizations, limit severe cases, and transform the seasonal management of RSV. The challenge is no longer only to treat bronchiolitis, but to prevent the virus’s systemic impact on child health upstream.   

Read next: Allergies and respiratory infections: toward a universal respiratory vaccine?

About the author – Ana Espino
PhD in Immunology, specialized in Virology  
As a scientific writer, Ana is passionate about bridging the gap between research and real-world impact. With expertise in immunology, virology, oncology, and clinical studies, she makes complex science clear and accessible. Her mission: to accelerate knowledge sharing and empower evidence-based decisions through impactful communication.