> It's hard to see how helping pigs stay healthy could have a negative impact on human health

I think that view underscores the differences in approach and beliefs in the US and Europe (not that both views aren't represented on both sides of the Atlantic, just distributed differently). The Europeans frequently have the view: Prove to us that this is not dangerous. Otherwise we prefer not taking the chance that you might be wrong. The US version in our eyes is frequently: "You can't prove it's not safe".

In this case you could risk introducing even worse diseases, who have previous been kept in check by the competition from the viruses you're now eliminating.

None of those pigs are “healthy”. If we didn’t pump them full of antibiotics they would never see the slaughterhouse.

Because CRISPR isn’t nearly that precise or exact, it always has unforeseen random fall off effects. Also, who says that particular receptor ONLY prevents entry of a specific virus? It surely has other purposes that aren’t understood.

Are the pigs healthy? I think the sibling comment got to the heart of this a lot more directly.

There's an economic reward for keeping the pigs healthy enough to be harvested while spending the least amount of money on their environment. If this lowers the threshold for "healthy enough", or allows them to survive in an even worse, cheaper to maintain environment, that could introduce or exacerbate human health risks even if this change itself cannot.

There is also the animal welfare element, that has resonance to a lot of people. I am by no means a vegetarian, do not in principle object to killing animals for food. But the sheer scale of animal suffering in our food system gives me pause. I am reluctant to accept innovations that would allow us to increase the degree of suffering in exchange for an increase in output or decrease in price.

>> It's hard to see how helping pigs stay healthy could have a negative impact on human health, <<

Really? You don't see a logical flaw in your reasoning there?