What causes bronchiolitis?

Bronchiolitis is most commonly caused by the respiratory syncytial virus (RSV). Here we explain what RSV is, how common RSV can be and how to tell if your child has caught RSV.

What causes bronchiolitis?

Bronchiolitis is almost always caused by a virus. The most common virus that causes bronchiolitis is called respiratory syncytial virus or RSV.

When does RSV typically circulate?

In the UK, RSV circulates every year. It typically starts in October and lasts until March, with numbers peaking in December or January.

How common is RSV?

According to statistics from Public Health England, over 60% of children will have caught RSV by their first birthday. And over 80% will have caught the virus by the time they are two years old. Generally speaking, children cope better with RSV as they get older.

Who is at greater risk from RSV?

While most RSV infections cause a mild illness, babies less than six months old are more likely to develop more severe symptoms. Children born prematurely, or those with a long-term lung condition, are also at increased risk of developing a serious illness from RSV.

How can I tell if my child has caught RSV?

RSV infection symptoms are similar to the common cold. For adults and children alike, symptoms are usually mild and can include:

  • runny nose
  • mild cough
  • raised body temperature
  • headaches.

Not all babies infected with RSV or other viruses will go on to develop bronchiolitis.

What can I do to prevent the spread of RSV?

Viruses are spread through the coughs or sneezes of someone who is infected. They can be breathed in from the air or picked up from a surface like skin, toys or door handles.

Transmission of viruses such as RSV can be reduced by:

  • practising good hand hygiene (washing your hands with soap and water for at least 20 seconds)
  • wiping down surfaces
  • avoiding contact with people who have colds or cold-like symptoms.

You can help prevent your child from developing bronchiolitis by taking steps to stop the spreading of viruses.

Read next: How is bronchiolitis treated?

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