A spokeswoman for the AstraZeneca, which makes the vaccine, confirmed Wednesday that the company had "encountered some challenges with production of two of the four strains contained in our vaccine, which has impacted delivery timing."
So far, about 6 million doses of FluMist have been shipped in the United States. The company said an additional 3 million doses will be shipped through the end of November. AstraZeneca said it would continue to have additional doses available to meet late season demand.
In recent years, company has been shipping between 14 million and 15 million doses of FluMist each season.
"The CDC supports vaccinating as long as flu viruses are circulating," the company said. "We continue to support vaccination as soon as product is available and throughout the season."
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