FILE – Illinois Governor JB Pritzker during a COVID-19 press conference in Springfield, Ill. (Justin L. Fowler/The State Journal-Register via AP)

SPRINGFIELD, Ill. (WJPF) — Governor JB Pritzker has joined the governors of Michigan, Minnesota, and Wisconsin in sending a letter to the US Department of Health and Human Services, demanding the federal agency begin distributing doses of the COVID-19 vaccine currently held in reserve.

The letter states that vaccine delivery to the states has been much slower than expected.

Currently, the federal government is holding back over half of the vaccine doses produced so far. The reason is not clear.