(CNN) — Pfizer coming out with promising data about a coronavirus vaccine booster.
The company says it will apply for emergency use authorization for a third shot soon.
Researchers say a booster shot six to 12 months after full vaccination is likely to provide the highest level of protection—especially against the highly contagious delta variant.
Studies show antibody levels in people from 18 through 55 who get that third shot are five times higher.
And for those ages 65 to 85—antibody levels are 11 times higher.
Also pending approval, Pfizer says it wants to study an updated version of its vaccine.
The company's lead researcher says it would target the Delta variant, which currently represents 83 percent of COVID-19 cases in the U.S.