New evidence about the worldwide influenza pandemic of 1918-1919 indicates that getting the flu early protected many people against a second deadlier wave, an article co-authored by an NIH epidemiologist concludes.
American soldiers, British sailors and a group of British civilians who were afflicted by the first mild wave of influenza in early 1918 apparently were more immune than others to the severe clinical effects of a more virulent strain later in the year, according to the paper published in the Nov. 15 issue of the Journal of Infectious Diseases by medical historian John Barry, staff scientist Cécile Viboud, PhD, of the NIH’s Fogarty International Center and epidemiologist Lone Simonson, PhD, of the George Washington University.
"If a mild first wave is documented, the benefits of cross-protection during future waves should be considered before implementing public health interventions designed to limit exposure," the authors suggested.
Mark Miller, MD, director of the Fogarty Center’s Division of International Epidemiology and Population Studies, said the finding could have implications for future pandemics. “If a 1918-like pandemic were to repeat itself, the early circulation of less pathogenic pandemic viruses could provide some level of population immunity that would limit the full onslaught from the second wave.
"Together with historical data recently uncovered from Denmark and New York City, this study gives us a different look at the process of adaptation of novel pandemic influenza viruses to humans and the evolution of virulence," Viboud said.