Waiting in the wings: Why bird flu vaccines are a game-time decision

Sometimes, you can’t see a pandemic coming. But sometimes you can.

While COVID-19 took the world by surprise, experts are keeping their eye on other potential outbreaks and right now there’s one prime candidate: bird flu.

Scientists have been monitoring bird flu, also known as avian influenza, for decades. It sometimes jumps into humans — and when it does, it is often fatal.

Though many experts say the current risk to most people is low, researchers have been working to have human vaccines on standby, just in case. But the...