Fully vaccinated Americans could be rolling up their sleeves for another dose of the coronavirus vaccine as soon as next month.

The Biden administration is close to advising fully vaccinated Americans get COVID-19 booster shots eight months after their last vaccine. A source familiar with the discussions among administration health experts said this recommendation could come as soon as this week.

The plan was first reported by The New York Times and The Washington Post.

The boosters would be intended to protect against the highly contagious delta variant, which has caused caseloads in the U.S. to surge. A third shot for those who received the Pfizer or Moderna vaccines would also help with any waning effectiveness of the current shots.

The source familiar with these discussions said administering the boosters could begin as early as mid to late September, pending authorization from the Food and Drug Administration.

The New York Times reports officials expect those who received the one dose Johnson & Johnson vaccine will need a booster shot as well. The government is waiting on recommending a second dose of Johnson & Johnson until it receives results from the company's two-dose clinical trial.

News of this impending change in vaccine policy comes just days after federal health agencies said some people with compromised immune systems should get a third shot. That recommendation applied only to people who received two doses of the Pfizer or Moderna vaccines.

Data show that many immunocompromised patients, such as organ transplant recipients and others on immune-suppressing medications, have had weak responses to the initial doses of the vaccine.

Pfizer says a booster can help maintain a high level of protection

Pfizer and BioNTech announced Monday that they submitted initial data to the FDA to support the evaluation of a third dose of the companies' COVID-19 vaccine.

The companies' research showed a third dose of their vaccine boosts antibody response that exceeds the level seen after the initial two-dose regimen.

"Given the high levels of immune responses observed, a booster dose given within 6 to 12 months after the primary vaccination schedule may help maintain a high level of protection against COVID-19," Pfizer said in a statement.

NPR's Arnie Seipel contributed to this report.

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