The UN health agency on Wednesday stood by its advice on swine flu treatment with the antiviral drug Tamiflu in "severe and progressive" infections, despite a study which warned against use by children.
"WHO continues to recommend use of antivirals as treatment for people who are severely ill or are at risk of other health complications," the World Health Organisation said in a response to questions about the recent study.
However, it also stressed that the antiviral, made by Swiss pharmaceutical giant Roche, should not be taken by those showing just mild flu-like symptoms.
The study did not cover the current outbreak of swine flu.
But it suggested that antivirals may not significantly reduce the length of illness or prevent complications in children infected with the new A(H1N1) virus, the researchers said.
The WHO said it was "aware" of the study but stressed that it was on seasonal flu and not A(H1N1).
The organisation said Tuesday that some 1,462 people around the world had died from the swine flu virus since it first emerged in April.