Updated

The European Medicines Agency warns that young children given GlaxoSmithKline's swine flu shot may get a fever after their second dose.

In a statement issued Friday, the European drug regulator said data from GlaxoSmithKline PLC showed a higher number of children aged six months to 3 years had a fever after their second dose of the Pandemrix vaccine, compared with the first. Kids were also more likely to have side effects like muscle pain, drowsiness, and irritability.

The European regulator recommends children get two doses of swine flu vaccine, though Glaxo says one dose is enough.

Last month, Glaxo advised health authorities not to use one batch of its Canadian-manufactured swine flu vaccine in case it triggered life-threatening side effects like anaphylactic shock.