CNN  — 

Illinois Gov. J.B. Pritzker announced Thursday that all PreK-12 public school teachers and staff, all higher-education personnel and students, and health care workers in a variety of settings must be vaccinated against Covid-19 by September 5 or face regular testing requirements.

Illinois is also instituting a statewide indoor mask requirement, regardless of vaccination status, beginning Monday, he said.

Pritzker said the requirements are aimed at protecting the most vulnerable residents – children ineligible to be vaccinated and elderly people with weakened immune systems – as well as hospitals with limited staffing and space.

“My number one concern is right now keeping the health care system available, not just for people who may get Covid but for people who have other problems and are taken to the hospital,” he said.

From January to July, 98% of Covid-19 cases, 96% of hospitalizations and 95% of deaths were among unvaccinated, Pritzker said. The governor said the regions with the fewest number of vaccinated individuals are the same regions with “fewer hospitals and lower hospital capacity” and those communities are being hit the hardest.

Kindergarten teacher Shelly Kelly talks with her students as they line up on the first day of school for District 186 at Owen Marsh Elementary School in Springfield, Illinois, on Monday, August 23.

The new mandates coincide with the return to school and amid a recent rise in Covid-19 cases and hospitalizations in Illinois, although infections and hospitalizations remain well below the winter peaks. The US Food and Drug Administration gave full approval to the Pfizer/BioNTech Covid-19 vaccine on Monday, a move that opened the door for vaccine mandates.

About 59% of Illinois residents 12 and older are fully vaccinated, slightly below the national average, according to the US Centers for Disease Control and Prevention.

The city of Chicago reinstated an indoor mask mandate last week and on Wednesday announced plans to require city employees to be fully vaccinated by October 15.

“The data shows that getting vaccinated is the best way to protect yourself and those you come in contact with from serious illness, hospitalization, or death from Covid-19,” said Chicago Department of Public Health Commissioner Dr. Allison Arwady in a statement. “Adopting and implementing this requirement is the responsible, common-sense approach, which is why we’re seeing so many other government agencies, companies, institutions, and organizations pursue this course of action.”

Other cities and states have similarly begun to mandate vaccinations for certain employees, thereby raising the economic cost of being unvaccinated. New York City announced Monday that all Department of Education staff for public schools must be vaccinated against Covid-19.

The teacher vaccine mandate is particularly important because children under age 12 are not yet eligible to be vaccinated. Vaccinating all teachers would help create an immune shield around these unvaccinated students and help ensure schools can remain open and safe this coming school year.

The idea of a vaccine mandate is to provide a metaphorical stick that officials hope will push teachers to get vaccinated or face economic consequences.

CNN’s Carma Hassan contributed to this report.