H5N8 is currently not breaking out into humans as H5N1 and H7N9 are, it's mainly a concern in poultry at this point.
The thing that we really need to watch for that would indicate increased risk of a pandemic is H2H (human to human) transmissions, most especially sustained H2H (chains of transmission).
There will be an increasing number (due to seasonal effects) of H7N9 cases in humans but it would take large increases to indicate a significant change in risk level of an outbreak.
The virus must first acquire efficient H2H transmission before an pandemic is possible. That, hopefully, will give us enough time to have either a treatment or a vaccine, or preferably BOTH ready before a pandemic begins.