Iowa has asked the federal government to withhold more than one-quarter of its allotment of coronavirus vaccines this week because demand for the shots has waned across the state.

The Iowa Department of Public Health told the Des Moines Register on Saturday that the state declined to accept 18,300 of 34,300 doses of Moderna vaccine it was slated to receive this week, and 3,510 of 46,800 doses of Pfizer vaccine.

“Along with several other states, we are seeing a slowdown of vaccine administration, but we are working with our local partners and community leaders to determine where additional education is needed and to gain an understanding of the needs of each county’s unique population,” said Sarah Ekstrand, a spokeswoman for the state health department.

Gov. Kim Reynolds said Wednesday that 43 of the state’s 99 counties had declined all or part of their weekly vaccine allocations for the week of April 26.

The federal Centers for Disease Control and Prevention said nearly 55% of Iowa adults have received at least one dose of the vaccine and more than 40% have been fully vaccinated against the disease.

The state allotment of vaccines doesn’t include thousands of doses that are being distributed directly through a number of pharmacies and clinics in Iowa as part of a federal program.