Thankfully, we have learned — at the cost of tens of thousands of possibly preventable deaths — that COVID-19 finds nursing homes to be good hunting grounds.

All of Essex County’s 16 COVID deaths (including one who went home to Clinton County before dying) were related to the Essex Center nursing home and rehabilitation facility in Elizabethtown, and one of Franklin County’s two deaths was a resident of the Alice Center nursing home in Malone.

Back in May and June, more than 40% of U.S. deaths from the disease were related to long-term care facilities.

Since then, extraordinary steps taken to protect nursing home residents have paid off. By Tuesday, more than 247,000 Americans had perished from COVID-19. More than one-fourth of them were in nursing homes. That certainly is better than the rate last spring — but it is not acceptable.

Clearly, the coronavirus is on the offensive again. In some states, the peril is worse than ever. And nursing homes once again are prime targets.

The danger has not escaped the notice of some governors, who have stepped up action to safeguard long-term care facility residents. One excellent idea is frequent testing of nursing home employees, who clearly are the most likely sources of infections among their patients. Also, those tests need to be processed quickly; an 19-day lab lag time was a factor in the deadly outbreak at Essex Center this summer.

A new testing center at Adirondack Medical Center in Saranac Lake could be used for that purpose. So could rapid testing Essex and Franklin counties recently received from New York state. There should be no higher-priority place to protect than nursing homes.

Both state and federal officials should view the spike in COVID-19 cases as a serious threat to nursing home residents throughout the United States. Extraordinary efforts must be taken to protect them — or the cost in lives will grow by leaps and bounds.