The U.S. Food and Drug Administration (FDA) announced Wednesday that it has authorized updated coronavirus booster shots targeting the highly-contagious omicron variant.

"Today, the U.S. Food and Drug Administration amended the emergency use authorizations (EUAs) of the Moderna COVID-19 Vaccine and the Pfizer-BioNTech COVID-19 Vaccine to authorize bivalent formulations of the vaccines for use as a single booster dose at least two months following primary or booster vaccination," it said in a statement.

The Food and Drug Administration on Wednesday authorized new Covid booster shots from Moderna and Pfizer that more closely match the strains of the coronavirus that are currently circulating in the U.S.

Pfizer’s booster, made with partner BioNTech, is being authorized for people as young as 12 years old. The Moderna booster is being authorized for people ages 18 and up.

COVID-19 vaccines designed to target the omicron variant have just been authorized by the Food and Drug Administration. Both Pfizer / BioNTech and Moderna got the FDA’s sign-off for their booster doses of the reformulated shot. This is the first update to COVID-19 vaccines to be authorized in the United States.

The Pfizer / BioNTech booster is available to people 12 and older, and the Moderna shot will be available to people 18 and older. They’ll only be boosters — they can’t be used by people who haven’t already had their first doses.

The Pfizer-BioNTech COVID-19 vaccine is less effective against the Omicron virus variant than other strains of the CCP virus, the companies said Wednesday, citing interim results from a study they’re running.

Scientists found on average a more than 25-fold reduction in neutralizing antibodies against the Omicron variant compared to the wild type, “indicating that two doses of BNT162b2 may not be sufficient to protect against infection with the Omicron variant,” the companies said in a statement.

Pfizer and BioNTech said Wednesday that laboratory tests suggest that three doses of their coronavirus vaccine offer significant protection against the fast-spreading Omicron variant of the virus.

The companies said that tests of blood from people who received only two doses found much lower antibody levels against the Omicron variant compared with an earlier version of the virus. That finding indicates that two doses alone “may not be sufficient to protect against infection” by the new variant, the companies said.

People who have received two doses of the Pfizer-BioNTech Covid-19 vaccine are likely susceptible to infection from the Omicron variant of the coronavirus, but a third shot restores antibody activity against the virus, the companies said Wednesday.

It was Jan. 24, 2020 when BioNTech CEO Uğur Şahin knew that Covid-19 was likely to become a global pandemic. 

Though it was over a month and a half before the World Health Organization officially declared a pandemic, Sahin met with his wife, BioNTech’s co-founder and chief medical officer Özlem Türeci. Together, they agreed to redirect most of the company’s resources to developing a vaccine. 

The Pfizer-BioNTech COVID-19 vaccine was 100% effective in teens ages 12 to 15, the company said Wednesday, providing hope there will be an option for people under age 16 before the next school year.

Pfizer said it found 18 cases within a placebo group but none in the vaccine arm of a trial involving over 2,200 participants. The antibody response also exceeded levels detected in an earlier trial of people ages 16 to 25.

The company said it will amend its emergency-use filing with the Food and Drug Administration in the coming weeks, as they target a rollout before fall.

New clinical trials showed that Pfizer's COVID-19 vaccine elicits "100% efficacy and robust antibody responses" in adolescents from 12-15 years old, the drug company announced Wednesday. The trial included 2,260 trial participants; the results are even better than earlier responses from participants ages 16-25.

Pfizer and its vaccine partner BioNTech say they will submit the results "as soon as possible" to the U.S. Food and Drug Administration and the European Medicines Agency, asking regulators to expand their authorizations for the vaccine's use in young people.

Pfizer says its Covid-19 vaccine is safe and 100 percent effective in preventing the illness in teenagers ages 12 to 15.

"This is exactly the news that we hoped to hear," said Dr. Buddy Creech, a pediatric infectious disease expert at the Vanderbilt University Medical Center in Nashville, Tennessee. Creech was not involved in the Pfizer research.

The vaccine, given in two doses three weeks apart, is already cleared for emergency use in people ages 16 and up.