Top Highlights

• Each epidemic is a product of its time, a theory that dates back to Plutarch in the second century AD.
• Pandemic influenza remains the most daunting threat. Two main factors make influenza particularly dangerous. First, it is among the nimblest of viruses. One strain mutates and swaps genes with another, occasionally resulting in a strain against which humans have no defence. The second problem is that, once a strain exists, it can easily spread.
• The question is not whether a new pandemic will emerge, but when and how the world will respond. In the long term, changes in technology will help: the old way of developing flu vaccines – over months, using lots and lots of chickens’ eggs – will be replaced by nimbler methods that use plants or cell cultures. Most promisingly, scientists are worki...