I'm not so sure. Jet injectors have been around for a long time, used in mass inoculation drives in 3rd world countries and they found that diseases can spread by using it. It was conclusive to the point that WHO no longer recommends their use. Apparently even though the width required is small, diseases like hepatitis can get through. It's a fun idea, but this is firstly nothing new and I believe has no new means of dealing with contamination.
Uhhhh, except with heroin.
That boy ain't right.
The reduction in potential for blood born disease is a huge plus.