On Jan. 25, 1919, nearly 2,000 San Franciscans showed up at Dreamland Rink for a public meeting of the Anti-Mask League. In the midst of a renewed wave of pandemic influenza that was washing over the city, the Board of Supervisors had imposed, once more, a regulation requiring citizens to wear masks in public. This crowd, though, was tired of the pandemic and especially of wearing masks.

The directive requiring masks had not been imposed hastily or arbitrarily. During the fall and winter of 1918-1919, influenza raged around the globe in one of the worst disease outbreaks in human history. By pandemic’s end, roughly a third of the world’s population had been infected. Of the startling 50-100 million people who had died, some 675,000 were American.

The pandemic had first struck in Boston in late August, and gradually made its ways across the country, infecting the entire nation in a matter of weeks. San Francisco, like many West Coast cities, had hoped to be immune to the pandemic’s reach, but that dream was shattered when, by mid-October, the city was awash in illness and local leadership imposed its first round of public health measures to protect the citizenry. By late January, many San Franciscans had grown weary of the impositions and turned out to the Anti-Mask League meeting to make that fact clear. They passed resolutions disparaging the ordinance and declaring it “contrary to the desires of a majority of the people.”

Though it took place more than a century ago, this scene is highly resonant with events around the United States in recent days. Last Friday, some 2,000 people turned out at the Wisconsin State Capitol to demand that the Governor end the state’s stay-at-home order, which he recently extended to May 26. Protestors, many without masks, condemned the public health measures designed to save their lives. The beliefs that brought them there varied. Some, already facing layoffs, were legitimately worried about their economic wellbeing. Others claimed the orders were the result of an “evil cabal” or a ruse by the government to take away their freedoms. This was only the largest of what have become commonplace protests around the country. From Sacramento to Sarasota, Boise to Baton Rouge, Americans are defying public health restrictions to voice opposition to stay-at-home orders. But the story of San Francisco’s struggles a century ago—against the 1918-1919 influenza pandemic and against the public health measures designed to combat it—should give such protestors pause. Inadequate protective efforts, or their removal too early, can cost lives.