Not sure where the technology is exactly at, but I suspect we're no more than 5 years from major incident related to this.
Even this vaccine, we really don't know the long-term impacts or risks involved with this. For instance, this vaccine does appear more risky than the standard flu vaccine:
https://wonder.cdc.gov/controller/saved/D8/D137F981
Presumably this is due to increased inflammation. It's not hard to imagine that we'll be doing genetic editing soon enough with this (if we aren't already).