I think the largest of these traits being the fact that it is a...

I think the largest of these traits being the fact that it is a DNA based vaccine. Everyone reads the benefits of DNA vaccine eg. little side effects, easy/fast manufacture and cheap to make and supply but never takes in the other side. However, not a single DNA vaccine (infectious diseases) has ever been successful in human trials and this failing has largely been associated with dose dependency that is so far impossible to overcome. In my field (HIV) DNA vaccine have mostly been given up on, in one study that I recall they injected people with about 15 injections at one time and this only gave a 1/10 per weight of the small primate studies equivalent (and was not effective). Back on topic, the vaccine is being administered intradermally which presents other complications with few vaccines being effective in this method due to the immunological niche of the skin. I could go on with more but they get more complicated to explain simply and without the aid of diagrams it is near impossible.

Don’t get me wrong, the vaccine they have here is using a different stimulating system for the immune system than other vaccines. It may very well overcome some of the issues of dose dependency but as a scientist I’m less optimistic than most on this.