Respiratory syncytial virus (RSV) is a common infection in infants and circulates year-round in Singapore. It is one of the most frequent causes of bronchiolitis in young children.
Bronchiolitis occurs when the small airways in the lungs become inflamed and narrowed, making breathing more difficult. As a result, some babies with RSV may develop wheezing, rapid breathing, or signs of increased effort when breathing, rather than just a runny nose and cough.
Understanding how RSV can move from an upper respiratory infection to the lower airways helps parents recognise early warning signs and seek medical review promptly.
Bronchiolitis can be caused by several viruses, but RSV is one of the most frequently identified causes in infants.
In babies, the airways are smaller and more sensitive to inflammation. Even mild swelling or mucus build-up can significantly narrow these passages, making breathing harder. Bronchiolitis is therefore frequently seen in babies with RSV infections, especially during their first year of life.
Bronchiolitis is an infection of the smallest air passages in the lungs, called bronchioles. When these airways become inflamed and filled with mucus, airflow becomes restricted. As a result, babies may develop wheezing, rapid breathing or increased effort when breathing.
It is important not to confuse bronchiolitis with bronchitis. Bronchitis affects the larger airways and is more common in older children and adults, whereas bronchiolitis mainly affects infants and young children.
Although RSV can infect people of all ages, its impact is different in infants. Even mild narrowing of the small airways can significantly increase the effort required to breathe.
Infants breathe more rapidly and must coordinate sucking, swallowing and breathing during feeds. Respiratory strain can quickly affect feeding efficiency and energy levels.
While older children and adults with RSV often experience mild, cold-like symptoms, infants are more likely to develop lower airway involvement, such as bronchiolitis. This explains why the same virus can appear mild in one family member but more serious in a young baby.
When RSV progresses to bronchiolitis, symptoms usually go beyond those of a simple cold. Signs to look out for include:
The good news is that most infants with RSV, including those who develop bronchiolitis, recover fully with supportive care. Symptoms often peak over a few days before gradually improving.
However, it can sometimes be difficult to tell whether your baby’s condition is still mild or becoming more serious. A paediatric assessment can help clarify what is happening and provide reassurance. A doctor can listen to your baby’s chest, assess breathing effort, and advise on the next steps.
If your baby has wheeze, fast breathing or noticeable feeding changes, speak to SBCC Baby and Child Clinic for assessment and guidance. Early review can provide clarity, reassurance, and timely support for your child’s recovery.