A Pfizer representative told the FDA vaccine advisory committee in late October that a new formulation of the company's COVID-19 vaccine was not tested in clinical studies, rtnews.co.il reported. Documentation provided to the FDA by Pfizer in its request for Emergency Use Authorization for using the COVID vaccine on children indicates that ingredients in the vaccine had been replaced. "To provide a vaccine with an improved stability profile, the Pfizer-BioNTech COVID-19 Vaccine for use in children 5-11 years of age uses tromethamine (Tris) buffer instead of the phosphatebuffered saline (PBS) as used in the previous formulation and excludes sodium chloride and potassium chloride," the document says. Responding to a question from the committee, Pfizer representative William Gruber said that the new formulation with "tromethamine (Tris) buffer" had not been used in trials. "It was determined that the clinical studies were not required, because the [...] behavior [...] is expected to be the same," he said.
