The most frequent adverse reactions have been fever, nausea, headache, allergic reactions and injection site pain, but these were mostly non-serious and had been expected, the European Medicines Agency said.

The safety update is the first analysis of adverse reactions following the roll-out of three vaccines across Europe -- GlaxoSmithKline's Pandemrix, Novartis's Focetria and Baxter's Celvapan.

New clinical trial data did show a greater incidence of fever following the second dose of Pandemrix in babies from 6 to 35 months and an assessment of that data was ongoing, the agency added.

(Reporting by Ben Hirschler; Editing by Greg Mahlich)