Updated at 11 a.m. ET

After shocking instances of nursing homes failing to disclose the existence and extent of COVID-19 cases within their facilities, the federal government will require nursing homes to inform residents, their families and representatives when residents or staff contract the illness.

The Centers for Medicare & Medicaid Services announced Sunday night that notification must come within 12 hours of a confirmed single case of COVID-19. Residents, families and representatives must also be told when three or more individuals develop respiratory symptoms within a 72-hour period.

The new rules also require nursing homes to report COVID-19 cases directly to the Centers for Disease Control and Prevention as the CDC works to build a nationwide database of the occurrence of the illness. Nursing homes are already required to report such data to state and local public health officials.

"Nursing homes have been ground zero for COVID-19," Centers for Medicare & Medicaid Services Administrator Seema Verma said in a statement announcing the new rules, which she described as an effort to provide "transparent and timely information to residents and their families."

The new rules also require nursing homes to detail measures the facility is taking to mitigate the spread of the disease.

Outbreaks and deaths from COVID-19 have occurred at nursing homes across the country, which house among the most vulnerable of high-risk individuals. In Virginia, for example, more than half of the outbreaks have been in long-term-care facilities.

Florida Gov. Ron DeSantis has ordered the National Guard to test for the virus in nursing homes and assisted living facilities. DeSantis had declined to say which facilities have residents who tested positive but reversed course over the weekend, ordering state authorities to release names of facilities that have reported cases of COVID-19.

Copyright NPR 2021.