New research highlights that infants who experience severe respiratory syncytial virus infections face increased risk of structural lung changes that could impair their respiratory health into adulthood.

RT’s Three Key Takeaways:

  1. Infants and children under 2 years old who experience severe cases of respiratory syncytial virus (RSV) are likely to experience changes in lung structure and function that can adversely affect their respiratory health later in life.
  2. The study observed significant defects in lung elasticity and expansion capacity post severe RSV infection in infant mice, including an increase in the size of alveoli but a reduction in the number of individual alveoli, which suggests a permanent impact on lung architecture.
  3. Severe early-life RSV infection correlates with higher risks of respiratory issues such as asthma and allergies, alongside compromised lung function due to disrupted alveolarization, a critical process of lung development that normally continues into early childhood.

Infants and children who have severe cases of respiratory syncytial virus (RSV) before age 2 are likely to have changes to their lung structure and function that could affect respiratory health later in life. 

The study is published ahead of print in the American Journal of Physiology-Lung Cellular and Molecular Physiology and has been chosen as an APSselect article for April.

Impact of Severe RSV Infections

Most children contract RSV, a lower respiratory tract disease, before they are 2 years old. Mild forms of the disease mimic the common cold with symptoms such as coughing, runny nose, congestion and sneezing. Severe forms of RSV can include wheezing, trouble breathing and, when oxygen levels are compromised, a blue tinge to the skin. A severe infection can affect a child’s future health as well. 

“[S]evere early-life RSV infection is associated with childhood wheezing related to respiratory viral infection exacerbation, allergies and asthma, that is accompanied by compromised lung function,” the researchers write.

Research Methodology and Findings

To study severe RSV, the researchers measured lung function and alveolarization in infant mice. Alveolarization is the development of alveoli, the sacs in the lungs responsible for exchanging oxygen and carbon dioxide. 

“Alveolarization continues into adulthood with maximum alveolarization occurring between [2 and 3 years old] in humans,” the team writes. Production of large numbers of immune cells occurs around the same time.

The researchers measured these markers at five weeks and three months after the initial RSV infection and again after a reinfection with the virus. They found “significant defects” in the ability of the lungs to stretch and expand during breathing. Structural changes to the mice’s lungs included an increase in alveoli size but fewer individual alveoli after RSV infection.

“These data indicate that the lungs of mice following an early-life RSV infection have a decreased lung function even at [three months] postinfection,” the research team writes. “Importantly, the structural defects of the early-life infected mice largely mimic the clinical setting where severe exacerbations are observed in children for several years following a severe early-life respiratory infection, especially RSV.”

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