JACKSON, Miss. — When the coronavirus first scythed through the nation in early 2020, few places needed help fighting it more than Scott County, Miss., a rural patch of chicken processing plants and pine forests an hour east of the state capital, Jackson.

The poverty rate for the county’s 28,000 residents was far above the nation’s. So, too, were rates of diabetes and other chronic illnesses that worsen the risk of severe Covid-19. Yet Mississippi’s health department, struggling under huge budget cuts ordered by the state’s Legislature, had deployed just two nurse practitioners to cover a quarter-million residents in Scott and eight other counties.

If it wasn’t clear enough during the Covid-19 pandemic, it has become obvious during the monkeypox outbreak: The United States, among the richest, most advanced nations in the world, remains wholly unprepared to combat new pathogens.

The coronavirus was a sly, unexpected adversary. Monkeypox was a familiar foe, and tests, vaccines and treatments were already at hand. But the response to both threats sputtered and stumbled at every step.

“It’s kind of like we’re seeing the tape replayed, except some of the excuses that we were relying on to rationalize what happened back in 2020 don’t apply here,” said Sam Scarpino, who leads pathogen surveillance at the Rockefeller Foundation’s Pandemic Prevention Institute.