From 2005:
https://topdocumentaryfilms.com/coming-pandemic/
Whether it's the seemingly annual discovery of a new flu-like virus accompanied by doom-and-gloom press coverage, or the popularity of viral-born zombie epidemics in Hollywood fare these days, or some other form of allusion to an impending cataclysmic viral outbreak, the possibility of a virus bringing entire nations, or even the world, to its knees is becoming an increasingly viable disaster. The Coming Pandemic explores this possibility in a range of hypothetical scenarios piggybacking off semi-actual medical findings and studies.
The film opens on establishing a foundation for the plausibility of a major incident, first in citing historical precedent with the Spanish Flu pandemic that occurred at the tail end of World War I, when soldiers brought home the virus when returning from their service, and then in following a hypothetical trip a young backpacker takes through Asia - he sits on a bus next to a woman infected with bird flu, ingests the airborne virus, and then carries it home with him.
A real-world incident is then examined by the filmmakers, the first recorded cases of the H1N1 virus, which first passed to humans after infected ducks (water born fowl are the most high-risk animals for these kinds of bird flu) were introduced to a chicken population in a small Asian village. When the chickens became ill and died, the farmers didn't think anything of it and decided to distribute the chickens for free anyhow - which of course resulted in the people that ate them contracting the virus.
As alarming as this was and is, scientists have yet to see this virus be passed from human to human, which puts them at ease about the risk we are actually at when it comes to an outbreak. This carries the film to the topic of what actually causes a widespread pandemic, a virus that humans have no immunity to whatsoever, and that occurs when a major mutation is developed in a viral strain. From there, a number of hypothetical scenarios are discussed by various scientists and medical industry professionals, including some of the political ramifications of these types of incidents.