NEW ORLEANS (AP) — New Orleans rushed to build a makeshift hospital in its convention center Friday as troubling new outbreaks bubbled in the United States, deaths surged in Italy and Spain and the world warily trudged through the pandemic that has sickened more than a half-million people.

Punctuating the fact that no one is immune to the new coronavirus, it pierced even the highest echelons of global power, with British Prime Minister Boris Johnson becoming the first leader of a major country to test positive.

While New York remained the worst hit city in the U.S., Americans braced for worsening conditions elsewhere, with worrisome infection numbers being reported in New Orleans, Chicago and Detroit.

“We are not through this. We’re not even halfway through this,” said Joseph Kanter of the Louisiana Department of Health, which has recorded more than 2,700 cases, more than five times what it had a week ago. The United States became the first country to surpass 100,000 infections on Friday, according to a count kept by Johns Hopkins University.

New Orleans’ sprawling Ernest N. Morial Convention Center, along the Mississippi River, was being converted into a massive hospital as officials prepared for thousands more patients than they could accommodate. The preparations immediately conjured images of another disaster, Hurricane Katrina in 2005, when the convention center became a squalid shelter of last resort in a city that has braved a string of storm hits.

As the new health crisis loomed, economic catastrophe had already arrived in the city, where many already live in poverty and the tourism industry has screeched to a halt.

In New York, where there are more than 44,000 cases statewide, the number of people hospitalized with COVID-19 passed 6,000 on Friday, double what it had been three days earlier.