MedImmune announced that the FDA has approved the use of its FluMist in children 2-5 years old, an indication that significantly expands the market for the nasal vaccine.

The company, which AstraZeneca acquired for $15.6 billion in June, had initially seen disappointing returns on the product, approved in 2003 for patients ages 5-49, due to its onerous storage requirements and its age restrictions – the very young and old being the most vulnerable to influenza. It brought in a meager $36.4 million last year.

However, the company won approval for a new formulation that could be stored refrigerated instead of frozen early this year, and now, with access to one of the prime markets for flu vaccines, the product’s prospects are looking brighter.