Pfizer is reportedly seeking approval for a 4th dose of COVID-19 vaccines for seniors

Pfizer is expected to seek authorization for a fourth dose in its COVID-19 vaccine regimen for seniors, The Associated Press reported Tuesday.

The additional booster shot would go to Americans ages 65 and up, in an effort to provide additional protection to age groups that are more vulnerable to serious illness by the coronavirus.

The request to the Food and Drug Administration and the Centers for Disease Control has not yet been submitted, but Pfizer's CEO Albert Bourla said earlier this week he believes a fourth dose is necessary. "The protection that you are getting from the third [dose], it is good enough, actually quite good for hospitalizations and deaths," he told CBS' Face the Nation. "It's not that good against infections, but doesn't last very long. But we are just submitting those data to the FDA and then we will see what the experts also will say outside Pfizer."

Pfizer has rolled out COVID-19 vaccines and boosters with varying regimens for specific age groups. Most recently, it postponed its request for approval for a shot for kids under age 5, saying it wants to compare data between a two-dose and three-dose regimen.