Moderna COVID-19 vaccine

Boxes containing the Moderna COVID-19 vaccine are prepared to be shipped at the McKesson distribution center in Olive Branch, Miss., Sunday, Dec. 20, 2020. (AP Photo/Paul Sancya, Pool)

LOUISVILLE, Ky. (WDRB) -- Moderna says it's developing a 2-in-1 vaccine booster that will protect against both COVID-19 and the flu.

The shot will combine Moderna's current COVID-19 vaccine with a new flu vaccine that is still under development.

The company hasn't said when trials for its new hybrid vaccine would start.

The Centers for Disease Control and Prevention (CDC) said more than 147 million Moderna vaccines have been administered in the United States.

Moderna said Thursday it has seen "robust antibody responses" during the second phase of studying the booster dose of its COVID-19 vaccine. It's still waiting for approval from the Food and Drug Administration (FDA), which is set to hold a meeting next week with outside advisors on COVID booster shots.

Following the announcement, Moderna's shares were up more than 5% in Thursday's trading session.

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