The early interventions implemented in St. Louis during the 1918 influenza pandemic led to lower death rates than in Philadelphia, a city that implemented interventions later.
Published March 17, 2020
By Timothy F. Murphy, MD
Infectious Diseases Physician Scientist, SUNY Distinguished Professor
Director, Clinical and Translational Science Institute
Last week I had multiple conversations with people who asked, “Why are we taking such drastic measures when there aren’t even any coronavirus infections in Western New York?” The dominoes fell quickly soon after with SUNY classes going online, innumerable events that involve crowds being canceled, the entire sports world grinding to a halt, and inevitable school closings. These are unprecedented times with the COVID-19 global pandemic that is affecting our community.
How do we know that these restrictions and interventions, that are dramatically altering life as we know it, will do anything to limit or prevent coronavirus infections? The 1918 influenza pandemic, which killed ~600,000 people in the U.S. alone, holds important lessons regarding implementing these interventions in communities.
The intensity of the 1918 pandemic varied widely among U.S. cities. The manner in which cities implemented interventions to limit spread of infection and fatalities also varied. The goal of implementing interventions like social distancing is to reduce disease transmission. Social distancing refers to measures to reduce contact among people, including working remotely, school closures, bans on gatherings, etc. What is the evidence that such interventions are effective?
“The evidence is clear that a community-wide effort will reduce transmission of coronavirus infection. But, it will only work if we all do it. This is taking evidenced-based proactive measures to reduce the burden on the healthcare system and, most importantly, to save lives in our community.”
In an elegant study, Hatchett and colleagues (Proceedings of the National Academy of Sciences of the United States of America 2007) analyzed data on the implementation and timing of interventions among different U.S. cities. A comparison of Philadelphia and St. Louis, the third and fourth largest U.S. cities in 1918, revealed the striking impact of the timing of implementation of interventions (see figure above). Based on data from 17 cities, the authors found that cities that implemented interventions early in the outbreak had peak death rates 50% lower than those who implemented later. And importantly, early implementation was associated with a 20% lower cumulative excess mortality compared to later implementation. That means that the bold steps being taken in Western New York before there is widespread disease place our community in a position to reduce coronavirus transmission and save lives.
Of the 19 different interventions employed, four involving social distancing were the most effective: closing schools, closing churches, closing theaters and banning public gatherings.
What does this information mean to us as individuals? In order for social distancing to be effective in preventing transmission in Western New York, each of us needs to commit to it. Coronavirus generally causes mild illness in young, otherwise healthy people, creating the temptation to ignore guidelines. However, there is no doubt that transmission in large numbers of young people will result in increased disease and death in older co-workers, friends, relatives, those with underlying illnesses, and, importantly, healthcare workers. This is why closing schools is the single most important intervention to reduce transmission in a community, even though the illness is mild in children.
So my message is for each of us to commit to social distancing, recognizing that this will change life the way we know it for the next couple of months. If you are reluctant to do it for yourself, do it for your co-workers, family and friends. The evidence is clear that a community-wide effort will reduce transmission of coronavirus infection. But, it will only work if we all do it. This is not panicking. This is taking evidenced-based proactive measures to reduce the burden on the healthcare system and, most importantly, to save lives in our community.