WASHINGTON - An advisory panel for the U.S. Food and Drug Administration on Friday voted to reject a plan to offer a booster dose of Pfizer-BioNTech’s COVID-19 vaccine for Americans saying more data is needed to determine if boosters are safe and effective.The vote by the committee of outside experts assembled by the Food and Drug Administration was 16-12, with members expressing frustration that Pfizer had provided little data on the safety of extra doses.