Pfizer is expected to seek authorization from the Food and Drug Administration to administer a third dose of its coronavirus vaccine to boost immunity and potentially stop the spread of coronavirus variants, according to AP.

Why it matters: Pfizer and BioNTech released the initial results of a study into coronavirus booster shots, finding that a third dose was five to 10 times more effective at neutralizing the virus than two doses.

Editor's note: This story is breaking. Check back for more details.