Moderna is seeking approval for a fourth COVID-19 vaccination shot, pending a grant for emergency authorization use from the Food and Drug Administration, the company announced Thursday.

If approved, this would be the second booster shot Moderna has issued for people ages 18 and up.

“The request to include adults over 18 years of age was made to provide flexibility for the U.S. Centers for Disease Control and Prevention (CDC) and healthcare providers to determine the appropriate use of an additional booster dose of mRNA-1273, including for those at higher risk of COVID-19…” the company said in a statement.