Pfizer proposes expansion of late-stage coronavirus vaccine trial

Pfizer and BioNTech said their late-stage trial is proceeding as planned and they expect to have enrolled 30,000 participants by next week. The two companies announced Saturday that they have submitted a proposal to the FDA to expand the phase-three trial of its coronavirus vaccine to include up to 44,000 participants. The expansion would help the companies ensure that their trial participants reflect a diverse population, especially with regard to people with underlying health conditions.