Des Moines Register: Polk County will expand coronavirus vaccinations next week to include people ages 16 to 64 with a wide range of health conditions, the county’s health department announced today. State officials announced March 4 that counties could make that move starting this week, if they had enough vaccine available. Polk County did not immediately do so, because its health leaders said they still were working to vaccinate seniors, school staffers and members of other groups that were previously eligible. Polk County Health Department Director Helen Eddy said today that her agency now believes it has enough vaccine to expand eligibility on Monday.