Over the past two years, historians and analysts have compared the coronavirus to the 1918 flu pandemic. Many of the mitigation practices used to combat the spread of the coronavirus, especially before the development of the vaccines, have been the same as those used in 1918 and 1919 — masks and hygiene, social distancing, ventilation, limits on gatherings (particularly indoors), quarantines, mandates, closure policies and more.

Yet, it may be that only now, in the winter of 2022, when Americans are exhausted with these mitigation methods, that a comparison to the 1918 pandemic is most apt.

The highly contagious omicron variant has rendered vaccines much less effective at preventing infections, thus producing skyrocketing caseloads. And that creates a direct parallel with the fall of 1918, which provides lessons for making January as painless as possible.

In February and March 1918, an infectious flu emerged. It spread from Kansas, through World War I troop and material transports, filling military post hospitals and traveling across the Atlantic and around the world within six months. Cramped quarters and wartime transport and industry generated optimal conditions for the flu to spread, and so, too, did the worldwide nature of commerce and connection. But there was a silver lining: Mortality rates were very low.

In part because of press censorship of anything that might undermine the war effort, many dismissed the flu as a “three-day fever,” perhaps merely a heavy cold, or simply another case of the grippe (an old-fashioned word for the flu).

Downplaying the flu led to high infection rates, which increased the odds of mutations. And in the summer of 1918, a more infectious variant emerged. In August and September, U.S. and British intelligence officers observed outbreaks in Switzerland and northern Europe, writing home with warnings that went largely unheeded.

Unsurprisingly then, this seemingly more infectious, much more deadly variant of H1N1 traveled west across the Atlantic, producing the worst period of the pandemic in October 1918. Nearly 200,000 Americans died that month. After a superspreading Liberty Loan parade at the end of September, Philadelphia became an epicenter of the outbreak. At its peak, nearly 700 Philadelphians died per day.