SARS:

SARS now also arrived in the UK. They might be able to isolate this case but looking at what's happening in China, I suspect the genie is out of the bottle. Still, many people believe this only attacks people with a weakened immune system. I cannot see this, in Hong Kong and China it attacks and kills healthy vital people as well as weakened people. 5% mortality is unacceptable to me. That would mean that if an epidemic broke loose in my country it would result in about 800.000 dead! Unacceptable! Yet, it is so.

5% does not sound much until you translate it to absolute numbers: 800.000 dead.