Update (January 31, 2022): The FDA has now granted full approval to Moderna's COVID-19 vaccine as well.

Update (October 29): The US Food and Drug Administration has granted an emergency use authorization for the use of Pfizer-BioNTech's COVID-19 vaccine in children aged 5 to 11 years, NPR and other outlets report.

Today (August 23), the United States Food and Drug Administration announced the approval of the Pfizer-BioNTech COVID-19 vaccine, making it the first fully approved COVID-19 vaccine in the country, according to a statement from the federal agency. The vaccine is now fully approved for use in individuals ages 16 and older—but remains in the emergency use authorization (EUA) stage for children ages 12 to 15, as well as in the context of third doses for immunocompromised persons.

Since December 11, 2020 the Pfizer-BioNTech vaccine has been in use in the US under EUA, a designation the FDA uses during public health emergencies when it determines that the benefits of a new medical product outweigh the risks. Now that it is fully approved, the vaccine will be marketed under the name Comirnaty.

“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,” says Janet Woodcock, acting FDA commissioner, in the statement. “Today’s milestone puts us one step closer to altering the course of this pandemic in the U.S.” 

As part of the approval process, the FDA reviewed efficacy and safety data from clinical trials involving 44,000 clinical trial participants around the world, including in the United States, South America, the European Union, and South Africa, The New York Times reports. According to the FDA’s statement, Pfizer has also been tracking about 12,000 vaccine recipients for at least six months to get longer-term safety and efficacy data. The AP reports that in the six months following the second dose, the vaccine is 97 percent effective against severe COVID-19, and 84 percent effective against mild infection. 

In addition to the formal clinical trial data, the AP reports that more than 200 million Pfizer vaccine doses have been administered in the US. According to the US Centers for Disease Control and Prevention (CDC), the most common vaccine side effects are mild, and include muscle pain, fatigue, and pain at the injection site. Serious side effects can occur, including chest pain and heart inflammation shortly following the second dose, but these are very rare. The CDC has reported 762 confirmed cases of heart inflammation, called myocarditis and pericarditis, following vaccination as of August 11. 

“People who say they don’t want to be first in line [to get the vaccine] don’t have that to worry about,” London School of Hygiene & Tropical Medicine anthropologist and vaccine confidence researcher Heidi Larson tells The Washington Post

Whether or not full FDA approval will improve confidence among the vaccine-hesitant remains to be seen, and according to the Post, some experts think the biggest push for new vaccinations coming on the heels of the approval will come from employers and organizations that may be more inclined to mandate the vaccine now that it is fully approved. “My expectation is that the biggest change will likely be less from individuals and more from organizations, be they industry, municipalities, etc.,” University of Maryland vaccine acceptance researcher Sandra Quinn tells the newspaper

“Mandating becomes much easier when you have full approval,” Emory University epidemiologist Carlos del Rio tells the AP. “I think a lot of businesses have been waiting for it.”

CNN reports that several large corporations, including Disney, Walmart, United Airlines, Facebook, Google, and Microsoft have announced plans to require vaccinations for employees, and a memo from the Pentagon earlier this month states that the COVID-19 vaccine will be mandatory for service members beginning “no later than mid-September, or immediately upon the U.S. Food and Drug Administration (FDA) licensure, whichever comes first.”

According to the Post, Moderna applied for full FDA approval on June 1 of this year, and Johnson & Johnson is planning to apply later this year. Both Pfizer-BioNTech and Moderna are conducting safety studies in children under 12, and both are expected to file their data with the FDA later this year.

“We’ve heard false claims that COVID-19 vaccines cause infertility, contain microchips, and cause COVID-19. And worse, we’ve heard false claims that thousands of people have died from the vaccine,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, at a press conference, according to Buzzfeed“Let me be clear: These claims are simply not true. Getting a COVID-19 vaccine can save your life.”