Pfizer anticipates applying for emergency use authorization of a third dose of its coronavirus vaccine as soon as next month, Dr. Mikael Dolsten, who leads worldwide research, development and medical for Pfizer, said during a company earnings call on Wednesday morning.
"We are in ongoing discussions with regulatory agencies regarding a potential third-dose booster of the current vaccine and, assuming positive results, anticipate an emergency use authorization submission as early as August," Dolsten said.
In order for third doses to be administered to people in the United States, the emergency use authorization that the US Food and Drug Administration issued for the vaccine would either need to be amended or, if the vaccine were FDA approved, a third dose could be given off label.
"We continue to believe it is likely that a third-dose booster may be needed within six to 12 months after full vaccination to maintain the highest level of protection, and studies are underway to evaluate the safety and immunogenicity of a third dose," Dolsten said, adding that data suggest antibody levels appear to decline around eight months after receiving a second dose of vaccine.
"Pending regulatory approval, we also plan to start an immunogenicity and safety study in August to evaluate an updated version of our vaccine specifically designed to target the Delta variant," Dolsten said.
He mentioned how the Delta variant is the "most transmissible" yet seen and now represents about 83% of sequenced Covid-19 cases in the United States.