[BostonCard]

I thought this visualization was useful to understand the effect of travel restrictions, and why most epidemiologists believe they are ineffective.  It is based on travel out of Wuhan to the rest of China, but the same models are used to evaluate travel between nations.



As you can see, even a pretty comprehensive travel restriction only buys you a few days and does nothing to reduce the magnitude of the peak of the outbreak.  That's because once an epidemic takes hold in an area, growth from community spread is much larger than growth of imported cases.  I view it a bit like a forest fire giving off burning embers which could light a nearby house.  If you cut down on the number of embers that are given off that might delay when the house catches fire, but if there is already a small fire in the house, preventing more embers from hitting the house is going to be of limited benefit unless you can put out the fire that is already in the house.

That's illustrated by the figure below:



A travel ban can only work if it is implemented in conjunction with other measures to reduce the community spread of infection.  The travel time might buy you some time, but it won't prevent an outbreak.  Social distancing can keep a lid on community spread.

The administration implemented a travel ban and declared victory.  A little bit like George W. Bush's "Mission Accomplished" victory lap.

Figures from the awesome medium medium post by Tomas Pueyo: https://medium.com/@tomaspueyo/coronavir...d3d9cd99ca

BC

[BostonCard]

I thought this visualization was useful to understand the effect of travel restrictions, and why most epidemiologists believe they are ineffective.  It is based on travel out of Wuhan to the rest of China, but the same models are used to evaluate travel between nations.



As you can see, even a pretty comprehensive travel restriction only buys you a few days and does nothing to reduce the magnitude of the peak of the outbreak.  That's because once an epidemic takes hold in an area, growth from community spread is much larger than growth of imported cases.  I view it a bit like a forest fire giving off burning embers which could light a nearby house.  If you cut down on the number of embers that are given off that might delay when the house catches fire, but if there is already a small fire in the house, preventing more embers from hitting the house is going to be of limited benefit unless you can put out the fire that is already in the house.

That's illustrated by the figure below:



A travel ban can only work if it is implemented in conjunction with other measures to reduce the community spread of infection.  The travel time might buy you some time, but it won't prevent an outbreak.  Social distancing can keep a lid on community spread.

The administration implemented a travel ban and declared victory.  A little bit like George W. Bush's "Mission Accomplished" victory lap.

Figures from the awesome medium medium post by Tomas Pueyo: https://medium.com/@tomaspueyo/coronavir...d3d9cd99ca

BC