MADISON, Wis. (AP) — States asked the federal government this week to withhold staggering amounts of COVID-19 vaccine amid plummeting demand for the shots, contributing to a growing U.S. stockpile of doses.

From South Carolina to Washington, states are requesting the Biden administration send them only a fraction of what’s been allocated to them. The turned-down vaccines amount to hundreds of thousands of doses this week alone, providing a stark illustration of the problem of vaccine hesitancy in the U.S.

More than 150 million Americans — about 57% of the adult population — have received at least one dose of vaccine, but government leaders from the Biden administration down to the city and county level are doing everything they can to persuade the rest of the country to get inoculated.

U.S. Surgeon General Vivek Murthy said Friday that the federal government has dedicated $250 million for community organizations to promote vaccinations, make appointments and provide transportation.