Companies that manufacture COVID-19 vaccines have pledged to conduct fresh trials for the shots, according to newly released documents.
Pfizer and BioNTech have committed to carrying out a randomized, double-blind, placebo-controlled trial to evaluate the safety and efficacy of their COVID-19 vaccine in adults aged 50 to 64 who do not have any conditions that are said to place them at increased risk for severe COVID-19, Dr. David Kaslow, an official with the Food and Drug Administration, said in one of the documents, an approval letter to the companies, dated Aug. 27.
