WASHINGTON (NewsNation Now) — The U.S. Food and Drug Administration gave full approval to Pfizer’s COVID-19 vaccine on Monday, a milestone that may help lift public confidence in the shots as the nation battles the most contagious coronavirus mutation yet.

The approval could boost the vaccination campaign by convincing more unvaccinated Americans that Pfizer’s shot is safe and effective and also make officials more comfortable implementing vaccine mandates.

Vaccine hesitancy has been a major hurdle to the White House’s goal of getting all eligible Americans vaccinated against the coronavirus.

“While millions of people have already safely received COVID-19 vaccines, we recognize that for some, the FDA approval of a vaccine may now instill additional confidence to get vaccinated. Today’s milestone puts us one step closer to altering the course of this pandemic in the U.S.,” said Acting FDA Commissioner Janet Woodcock, M.D.

President Joe Biden praised the move by the FDA adding that he hopes this allows more businesses to require COVID-19 vaccines.

“With today’s full FDA approval, there’s another good reason to get vaccinated,” he said during remarks Monday.

U.S. vaccinations bottomed out in July. As the delta variant fills hospital beds, shots are on the rise again — with a million a day given Thursday, Friday and Saturday.  Just over half of the U.S. population is fully vaccinated with one of the country’s three options, from Pfizer, Moderna or Johnson & Johnson.

The U.S. becomes the first country to fully approve the shot, according to Pfizer, and CEO Albert Bourla said in a statement he hoped the decision “will help increase confidence in our vaccine, as vaccination remains the best tool we have to help protect lives.”

Full approval of Pfizer’s shot now makes it easier for physicians to prescribe a third booster shot to people who could benefit from an additional dose.

The FDA already is allowing emergency use of a third dose of either the Pfizer or Moderna vaccine for people with severely weakened immune systems, such as organ transplant recipients who don’t respond as strongly to the usual two shots. For everyone else who got those vaccinations, the Biden administration is planning ahead for booster starting in the fall — if the FDA and CDC agree.

Some experts, including at the World Health Organization, say there is not yet enough data to be certain that boosters are needed.

Pfizer’s vaccine was authorized for emergency use in December and more than 203 million people in the United States have so far received it. The Pentagon said Monday that it will issue guidance to make vaccine mandatory for the military now that the Pfizer vaccine is approved.

Even after hundreds of millions of shots, serious side effects — such as chest pain and heart inflammation in teens and young adults — remain exceedingly rare, the FDA said.

As for effectiveness, six-month tracking of Pfizer’s original study showed the vaccine remained 97% protective against severe COVID-19. Protection against milder infection waned slightly, from a peak of 96% two months after the second dose to 84% by six months.

Those data came before the extra-contagious delta variant began spreading, but other data from the Centers for Disease Control and Prevention shows the vaccine is still doing a good job preventing severe disease caused by that mutant.

As for all the talk about booster doses, the FDA’s licensure doesn’t cover those. The agency will decide that separately.

The FDA already is allowing emergency use of a third dose of either the Pfizer or Moderna vaccine for people with severely weakened immune systems, such as organ transplant recipients who don’t respond as strongly to the usual two shots. For everyone else who got those vaccinations, the Biden administration is planning ahead for booster starting in the fall — if the FDA and CDC agree.

Also still to be decided is vaccination of children under 12. Both Pfizer and Moderna are studying youngsters, with data expected in the fall.