The Spanish Flu of 1918 has so far been the most dangerous pandemic which affected approximately 500 million in just 2 years.
The SARS epidemic in 2002 was not scary because of the number of casualties but because it affected nearly ten thousand individuals across the world in the space of a few months.
We may have another such pandemic on our hands in a few years and it will be swift and deadly. There is little we can do to prevent it.
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