A hospital in Liverpool is dealing with an escalation in a children's chest disease.
The charity Action Research is funding research into bronchiolitis - the most common cause of infant admissions at Alder Hey Children's Hospital in Liverpool.
About 100 children with the disease have been admitted through the hospital's accident and emergency department.
A quarter of the beds in the intensive care unit are taken up with babies suffering bronchiolitis.
'Life-threatening'
Action Research says that cases have risen with the recent cold weather, but could increase further over the next few months.
Professor Rosalind Smith is based at Alder Hey and is leading a three-year research study.
She said: "There is much that we don't know about bronchiolitis and the underlying RSV infection, not least why it causes life-threatening chest infections in some infants, but trivial symptoms in others.
"There is a need to develop a vaccine to protect babies against infection and specific treatments for the condition.
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