The companies said this additional booster did not result in any new safety concerns. Although not included in the EUA submission, the companies referenced other "emerging evidence" that could support the need for an additional booster. "These early studies indicate that an additional booster dose of the Pfizer-BioNTech COVID-19 Vaccine administered at least 4 months after an initial booster dose could restore antibody titers to peak post-third dose titer levels, improve protection against both infection and severe disease in individuals 60 years of age and older in Israel, and have a similar safety profile to that of previous doses." The FDA said it will review Pfizer and BioNTech's request "as expeditiously as possible using our thorough and science-based approach."