Fauci said the federal definition of 'fully vaccinated' won't yet change to include booster shots

• Dr. Anthony Fauci said Sunday the federal definition of "fully vaccinated" won't yet change to include booster shoots.
• A person is currently considered fully vaccinated after receiving one shot of the Johson & Johnson vaccine or two doses of the Moderna and Pfizer vaccine.

Dr. Anthony Fauci, the longtime director of the National Institute of Allergy and Infectious Diseases, said Sunday that the federal government's definition of "fully vaccinated" wouldn't immediately change following the authorization of COVID-19 booster shots last week.

"First of all, you want to go with the science," Fauci told ABC News' Martha Raddatz during an appearance Sunday on "This Week."

For now, that data suggests maintaining the current guidelines for vaccination, he said. Currently, a person in the US is considered to have completed their vaccination after receiving one shot of Johnson & Johnson's vaccine or two doses of the mRNA vaccines made by Moderna and Pfizer.

Health officials were monitoring people who received booster shots to see what the "durability of that protection is," Fauci said.

"And as we always do, we just follow and let the data guide your policy and let the data guide your recommendations," said Fauci, the chief medical advisor to President Joe Biden.

As Insider previously reported, the US Food and Drug Administration last week expanded its emergency authorization for booster shot eligibility, making all adults eligible to receive them after previously allowing them for older and at-risk populations.

As a result, some state leaders have suggested their definition of fully vaccinated has changed, now requiring the booster dose.

"Authorizing the use of a single booster dose of either the Moderna or Pfizer-BioNTech COVID-19 vaccine for individuals 18 years of age and older helps to provide continued protection against COVID-19, including the serious consequences that can occur, such as hospitalization and death," said Dr. Janet Woodcock, acting commissioner of the FDA.

Adults who received the Johnson & Johnson vaccine can get an additional dose two months after their first, the FDA said. Adults who received either of the mRNA vaccines can get the booster dose six months after they were fully vaccinated. People under the age of 18 are still not eligible for booster shots.

According to data from the Centers for Disease Control and Prevention, just over 59% of people in the US have been fully vaccinated against COVID-19 under the current guidelines. About 17.6% of the US population has received a booster shot, per the CDC data.