Airborne spread is currently nonexistent in humans, because the H5N1 virus circulating in other mammals right now still lacks the exact right protein to bind to human lung cells. However, all this news about cows is a bit of a distraction. They're being infected in their udders, not their lungs, and that's why they're not dying en masse. Yet.
Sea lions are dying en masse. That's the big news. Because they are spreading it to each other's lungs through the air.
If it adapts to human lung cells it isn't going to be deniable that it's airborne and extremely deadly in that case.
The relevant authorities are currently waiting for that strain to emerge -it's called the pandemic strain- before declaring states of emergency and authorizing vaccines. The reason is that it is (A) unknown if or when that will happen, and (B) unknown whether a vaccine against the current strain which doesn't infect human lungs would be effective against the theoretical future mutant strain that does. Therefore from a public health perspective it's better in large bore to save the resources and not start producing a possibly useless vaccine now.
Sea lions are dying en masse. That's the big news. Because they are spreading it to each other's lungs through the air.
If it adapts to human lung cells it isn't going to be deniable that it's airborne and extremely deadly in that case.
The relevant authorities are currently waiting for that strain to emerge -it's called the pandemic strain- before declaring states of emergency and authorizing vaccines. The reason is that it is (A) unknown if or when that will happen, and (B) unknown whether a vaccine against the current strain which doesn't infect human lungs would be effective against the theoretical future mutant strain that does. Therefore from a public health perspective it's better in large bore to save the resources and not start producing a possibly useless vaccine now.