In the Proceedings of the National Academy of Sciences (PNAS), there is an interesting article about public health interventions to combat influenza epidemics. These nonpharmaceutical interventions (NPIs) include closure of schools, churches, and theaters. The authors find the following results:
“…cities in which multiple interventions were implemented at an early phase of the epidemic had peak death rates 50% lower than those that did not and had less-steep epidemic curves. Cities in which multiple interventions were implemented at an early phase of the epidemic also showed a trend toward lower cumulative excess mortality, but the difference was smaller (20%) and less statistically significant than that for peak death rates…These findings support the hypothesis that rapid implementation of multiple NPIs can significantly reduce influenza transmission, but that viral spread will be renewed upon relaxation of such measures.”
One issue to note is that the influenza epidemic hit first in East Coast cities such as Philadelphia. These cities were often slow to adopt NPIs. On the other hand, Midwestern cities such as St. Louis were hit with the epidemic weeks later. The Midwestern cities were able to learn from the experiences cities on the eastern seaboard and thus adopt more stringent interventions.