Investing.com -- Moderna Inc shares climbed 9.5%, trading over $57 in afternoon trading on Tuesday after U.S. Food and Drug Administration staff released positive assessments of the company's flu vaccine candidate.

FDA staff said in briefing documents that data showing a strong immune response to Moderna's flu shot may support its effectiveness in adults 65 years and older. The documents were published ahead of the regulator's advisory meeting scheduled for June 18.

The vaccine, called mFlusiva, demonstrated superior relative vaccine efficacy compared to a standard-dose flu vaccine in adults aged 50 to 64 years old, according to the FDA staff documents.

The FDA's advisory committee will vote on June 18 on whether mFlusiva's benefits outweigh its risks in adults 50 years and older. The panel will also evaluate whether the vaccine's benefits outweigh risks specifically in older adults.

FDA staff noted that Moderna's application for adults 65 and older relies mainly on immunogenicity data against a standard-dose vaccine rather than the Centers for Disease Control and Prevention-preferred high dose shots for older adults.