The pandemic took on Spain’s name only because its free press ambitiously reported the devastation in the disease’s early 1918 wave while government officials and a complicit press in countries at war — the US among them — played it down in a time of jingoism, censorship and denial.

Medical advice from then also resonates today: “If you get it, stay at home, rest in bed, keep warm, drink hot drinks and stay quiet until the symptoms are past,” said Dr. John Dill Robertson, Chicago health commissioner in 1918. “Then continue to be careful, for the greatest danger is from pneumonia or some kindred disease after the influenza is gone.”

In the manner of the day, there just had to be a catchy rhyme in circulation, too: “Cover up each cough and sneeze. If you don’t you’ll spread disease.”

But there were also marked differences between the viruses of 1918 and 2020. The Spanish flu was particularly dangerous to healthy people aged 20 to 40 — the prime generation of military service — paradoxically because of their vibrant immune systems.

When such people got infected, their antibodies went after the virus like soldiers spilling from the trenches of Europe’s killing fields.

“The immune system was throwing every weapon it had at the virus,” Barry said. “The battlefield was the lung. The lung was being destroyed in that battle.”

Young soldiers and sailors massed at military camps in the US, sailed for Europe on ships stuffed to the gunwales with humanity, fought side by side in the trenches and came home in victory to adoring crowds. The toll was enormous, on them and the people they infected. The Spanish flu could just as easily have been called the US Army or US Navy flu instead. Or the German or British flu, for that matter.

Among those who died in the pandemic was Friedrich Trump, Donald Trump’s paternal grandfather. Among those who contracted it and recovered were the wartime leaders of Britain and Germany as well as of the United States, British and Spanish kings and the future US president, Franklin Roosevelt, when he was assistant Navy secretary.

But the toll was heavier on average people and the poor, crowded in tenements, street cars and sweaty factories.

They could not all live by the words of the 1918 US surgeon general, Rupert Blue: “Keep out of crowds and stuffy places as much as possible … The value of fresh air through open windows cannot be overemphasised … Make every possible effort to breath as much pure air as possible.”