WASHINGTON (AP) – The Biden administration says it has the authority to direct states to open up their vaccine supply to all adult Americans by May 1 using the same mechanism it used to order that teachers and childcare workers become eligible earlier this month. States are required to distribute the federally provided vaccines in accordance with guidelines set by the Department of Health and Human Services. The department will issue a directive telling states to allow all adults to be vaccinated under their eligibility criteria by May 1. The federal government also controls supply directly through the federal retail pharmacy program, federally run mass vaccination sites and federally qualified community health centers and could use those mechanisms as well to expand eligibility.