With coronavirus infections, hospitalizations and deaths spiking across the country, and the Biden administration racing to vaccinate Americans, conspiracy theories about both the virus and vaccines have witnessed a worrisome surge. Such falsehoods will be a major impediment to the vaccine campaign. But history offers some hope for combating them — if policymakers target their root causes.

The United States witnessed a comparable outpouring of misinformation during the 1918 influenza pandemic. There were widespread claims that compulsory medical treatments for U.S. soldiers at training camps and military bases were driving the disease. Despite their inaccuracy, the claims spread widely among various communities who, marginalized by their race, gender, class, region, immigration status or a combination thereof, viewed state and health authorities as indifferent, exploitative or even repressive. These Americans’ valid concerns over government coercion and imperiled individual autonomy, rooted in their personal experiences and exacerbated by the uncertainties of extreme crisis, manifested in false stories about viral transmission and vaccination.

The lesson for the Biden administration is that these conspiracy theories proliferated most when they reflected and reinforced Americans’ preexisting anxieties over state power, scientific expertise and individual liberty. As such, dispelling conspiracy theories today requires addressing the underlying fears and concerns of people whose long-standing and often legitimate mistrust of government and the medical profession provides fertile ground for false information.

In autumn 1918, after first appearing among U.S. military personnel in the spring, a second and far deadlier wave of influenza began to ravage the nation. It attacked swiftly, striking down many young adults at the peak of their physical fitness who, having felt fine just several hours earlier, were suddenly prostrate with high fevers, weakness, severe aches and an intense irritation in their upper respiratory tracts. The influenza’s unprecedented tendency to cause pneumonia meant that many would die within just several days of infection.

The concentrated nature of the assault was astounding. In October 1918, Philadelphia witnessed 2,600 deaths in a single week and 4,500 in the week that followed, leaving a gruesome scene at the city’s only morgue. In that month alone, influenza claimed the lives of nearly 200,000 Americans, roughly quadrupling the country’s combat deaths for the entire war period.

The disease’s terrifying ability to so swiftly upend the rhythms and rituals of everyday life only added to the war’s larger social disruptions. Most notably, the Selective Service Act of May 1917 had rapidly expanded the U.S. Army from a mere 127,000 regular soldiers at the beginning of the conflict into an efficient, complex institution that would eventually pull some 4 million through its service. Throughout the war period, service members had to leave their occupations and families, travel to one of 32 training camps scattered across the country and face the prospect of deploying overseas, perhaps never to return.

The ongoing anxieties over soldiers’ survival joined the horror of influenza to produce a flood of conspiracy theories.

An increasing number of Americans heard and repeated the rumor that disloyal nurses and doctors throughout the nation’s training camps were injecting recruits with influenza germs — rather than required inoculations against typhoid and smallpox — to sabotage the war effort. “There was bound to be something wrong when the boys begun to die by the hundreds,” wrote one Texas woman to her sister in a letter intercepted by postal censors and forwarded to the Bureau of Investigation. She denounced the camp’s head nurse as “a German spy” and the “cause of more than half of the influenza in the camp.”