Isn’t that swell? Now how did it just happen to arrive ready to infect humans?
Influenza viruses preferentially attach to certain cell surface receptors that are most commonly found in birds and low in the human respiratory tract. Humans normally catch influenzas that are adapted to a variant of the receptor that is found in the upper respiratory tract. So humans do not easily catch bird flu viruses.
Pigs have both forms of the receptor in the upper respiratory tract. So a bird flu virus can infect pigs through the bird-like receptor and adapt in the pig to infect through the human-like receptor. At that point, the influenza can easily infect humans.
Humans can catch bird flus, but not readily. Once a human catches a bird flu, they can get VERY sick; some bird flus have a 60% death rate in humans. Bird flus are not very contagious between humans, because of the fact that they infect the lower respiratory tract.
So, what it looks like happened here is that a bird flu infected pigs and became adapted to be able to easily infect humans and be able to spread person to person.
This process actually happens fairly often, all over the world. Bird culls (usually of chickens) happen on a fairly regular basis in order to stop bird flus from spreading.
We plebians are not getting the whole story but we do know its coming from China.
One thing that's come out is unlike "normal" flu viruses, the body's antibodies may not last long.
More design features.
Fauci paid China for enhanced viruses or some such term because the research was blocked in the US, IIRC.
Why would anybody do that?