The outbreak of influenza that swept the globe in 1918 infected an estimated 500 million people — about one-third of the world’s population at the time — and killed between 20 million and 50 million people, including some 657,000 Americans. However, it has come to be known as “the forgotten pandemic” because the true impact of this medical catastrophe was overshadowed by the devastation of World War I, downplayed by the news media and burdened by poor record keeping.

Even more blurry, say the three members of a Johns Hopkins Medicine history and health equity research team, is the accounting of racial disparities and their effect on Black Americans during the 1918 pandemic. As described in a paper published earlier this month in the Annals of Internal Medicine, the researchers looked at primary sources from a century ago that addressed race as a health factor to gain insight and perspective into the “critical structural inequities and health care gaps” that are still problems for communities of color trying to persevere during the COVID-19 pandemic.

For example, the researchers note that “the few studies examining racial differences in the 1918 pandemic found that the Black population had lower influenza incidence and morbidity but higher case fatality.” The studies, they report, suggested that housing segregation, overcrowded and unsanitary living environments, and poor access to health care exposed Black Americans disproportionately to the flu during the first of three disease waves and, therefore, may have conferred protection against the second and third outbreaks. However, the researchers add, the same factors — along with higher risk for pulmonary disease, malnutrition, and social and economic disparities — made it more likely for Black Americans than white Americans to die from the flu.

The researchers also report that in Baltimore in 1918, “influenza overwhelmed medical resources straining under the burden of urban density, unequal living conditions and a high concentration of military training camps.” The records show, say the researchers, that by the time the city health commissioner admitted the seriousness of the outbreak and imposed restrictions, it was too late to curb the spread of the disease, especially among Black residents.

The researchers say there are important parallels between the 1918 influenza and the current COVID-19 pandemic, and that studying them allows us to “ground our current and future strategies in this historical context, deliver a more equitable pandemic strategy and reduce disparities in marginalized communities.” Based on their comparisons of today’s events with those in 1918, the researchers propose several areas for intervention and mobilization through the various phases of pandemic response.