Despite its name, The 1918 'Spanish' flu pandemic is thought to have first originated in the US. Now it seems history may be close to repeating itself. Throughout 2024 the H5N1 Bird Flu virus has been spreading among US cow herds and is now found in over 500 herds in 15 states. If it spreads to pig herds that is an even bigger problem. Historically, influenza in pigs has been much more likely to cause the genetic recombinations that create human-to-human transmissible diseases.
There's good news, and bad news.
The good news is that mRNA vaccines, in time, should be able to combat any human transmissible strain that arises - though it may take another global lockdown before they are developed and manufactured.
The bad news is that the human mortality rate could be much higher than Covid or Spanish flu. Some variants of H5N1 humans have picked up from animals seem to have near 50% mortality rates. We won't know if we get a milder version until/if it happens.
The worst news? Stopping this spreading to US pig herds will require extraordinary care and vigilance from numerous government public health agencies and everyone working on farms. Just at the moment the public have voted to put clowns in charge of those efforts, who are also talking about shutting them all down. Hubris like this almost begs to be punished by disaster.
That's kinda the opposite of what has historically happened. Black plague effectively killed many monarchys, and made "peasants" valuable again.