(NEXSTAR) – As the highly contagious delta variant spreads around the country, you may be looking for another layer of protection from the coronavirus (you know, other than a mask). So is it possible to get a third dose of the vaccine?

The short answer is not yet.

Pfizer plans to seek emergency use authorization from the Food and Drug Administration in August to start rolling out its third dose.

Even if Pfizer is granted authorization for another dose, it doesn’t mean you’ll be able to book your appointment right away. Public health officials will have to determine if they think booster shots are a priority given that 42% of eligible Americans still aren’t fully vaccinated.

Would a third dose help combat the spread of the delta variant?

Pfizer’s Dr. Mikael Dolsten told The Associated Press earlier this month that early data from the company’s booster study suggests people’s antibody levels jump five- to 10-fold after a third dose compared with their second dose months earlier.

That certainly sounds like it would make a big impact, but actually, the first two doses have already proven themselves pretty effective at fighting delta.

Researchers in Britain found two doses of the Pfizer vaccine, for example, are 96% protective against hospitalization with the delta variant and 88% effective against symptomatic infection. Canadian researchers found similar results, while a report from Israel suggested protection against mild delta infection may have dipped lower, to 64%.

The Associated Press contributed to this report.