As efforts continue to get more shots in arms, Pfizer says it will seek FDA authorization for a third dose of its coronavirus vaccine.

The booster shot would look to increase what the company is calling a "waning immunity" among those vaccinated.

Early data from the Pfizer's booster study found that a third dose, given six months after the second, generated antibody levels that were five to ten times higher than the two-dose regimen.

The company is also planning to tailor the third dose to target the the delta variant, which is the dominant strain of COVID-19 in the U.S.

Current evidence shows the Pfizer vaccine may not prevent the delta variant from creating mild disease, but it's highly effective in preventing severe disease and death.

Dr. James Kravec, the Chief Clinical Officer at Mercy Health Youngstown, says the potential authorization of a third dose doesn't mean those currently vaccinated aren't protected.

"You will have very, very high likelihood of not being infected with those first two doses. The third dose is really just a preparation for the future, preparation for changes, preparation for as immunity goes down," Kravec said.

Subject to approvals, clinical studies for the third dose could begin as early as August.