Cautionary Conversation: In 1990, a small extremist group launched a nerve gas attack on passengers riding the Tokyo subway. Thousands of people were hurt, more than a dozen died. At the time, such use of a chemical weapon seemed new and uniquely terrifying.

But advances in biology mean that today it's possible such a group could create a virus like Covid... with the potential to kill millions. What are the dangers and what can we do to combat them? Tim Harford talks to writer Michael Specter about his new book Higher Animals: Vaccines, Synthetic Biology and the Future of Life.

(Higher Animals: Vaccines, Synthetic Biology and the Future of Life is is available now at Pushkin.fm, Audible, or wherever audiobooks are sold.)