The American pharmaceutical company MedImmune Inc. expects to ramp up production of FluMist nasal flu vaccine next year after a newly built plant it owns in England received FDA approval, the company said Tuesday.

The Food and Drug Administration approval of the new Speke, England, plant clears the way for it to produce up to 15 million doses of FluMist a month, or 90 million doses each winter flu season, the Gaithersburg, Md.-based company said.

FluMist is the only available nasal-spray vaccine for the winter flu. It's also the only flu vaccine made with live but weakened influenza viruses.

Vaccine manufacturing capacity and availability have become major issues amid worries about a possible flu pandemic.

Last year, contamination issues led British regulators to shut down Chiron Corp., effectively cutting in half the 100 million flu vaccines expected on the U.S. market.

FluMist is suggested for use by healthy people between the ages of 5 and 49.