The Biden administration’s decisions over when to administer coronavirus vaccine boosters are triggering turmoil within the Food and Drug Administration, frustrating regulators and sparking fear that political pressures will once again override the agency’s expertise. FDA officials are scrambling to collect and analyze data that clearly demonstrate the boosters' benefits before the administration’s Sept. 20 deadline for rolling them out to most adults. Many outside experts, and some within the agency, see uncomfortable similarities between the Biden team's top-down booster plan and former President Donald Trump's attempts to goad FDA into accelerating its initial authorization process for Covid-19 vaccines and...