The Food and Drug Administration has given the green light to Pfizer booster shots for Americans over the age of 65 and those at high risk of developing severe COVID-19 symptoms.

The authorization, issued after the U.S. death toll surpassed that of the 1918 Spanish flu pandemic earlier this week, also comes after an FDA panel last week rejected a plan initially floated by the White House for all Americans to get Pfizer booster shots. Instead, the panel recommended that only higher risk groups go through a third round of the jab six months after their second dose.

Wednesday’s decision is in line with the panel’s recommendation, but it has caused some confusion in light of President Joe Biden’s announcement last month that all adults who received both doses of the Pfizer or Moderna vaccine would be able to get a booster shot starting the week of Sept. 20.

Asked to explain that discrepancy earlier this week, White House press secretary Jen Psaki on Monday noted that the surgeon General had made clear the booster plan was pending FDA approval.

“We’ve seen some recommendations that we felt was a step forward in providing more protection to people across the country. And we’ll wait for that process to play out,” she told reporters.

The FDA decision is also expected to be taken into consideration by a Centers for Disease Control and Prevention advisory panel meeting on Wednesday and Thursday to issue further recommendations on who should be eligible for booster shots.

Even if the CDC offers a different recommendation, however, the FDA decision allows health care providers to give Pfizer boosters to those who meet the criteria.