The Biden administration is reportedly planning to give Americans ages 50 and up the choice to receive a second COVID-19 booster dose of the Pfizer-BioNTech or Moderna vaccines.

The New York Times said Friday that the move would be made without “recommending outright” that the group get one, citing “several people familiar with the plan.”

However, the publication noted that “major uncertainties have complicated the decision,” including how long the protection from the second booster would last, as well as how to present the White House’s overall goal to the public.