I've had a few friends that became addicted to opioids over the last ~20 years. It's terrifying to see what it can do to a person, how the addiction takes over. The only product I've seen work consistently to stop relapse and interrupt the craving, is Suboxone and the equivalent. It worked extremely well, returned them to a fully normal functioning state, but they couldn't stop taking it.

The vaccination approach, even if it's unlikely to succeed, I certainly hope that it does, as every opioid addict I've known has ended up in a battle that never actually stops. It becomes a life-long struggle.