What are they? Legal ones?
I figure:
1) I know that in Russia, and I'm a russian who doesn't live there, and Kazakhstan, one can buy a real certificate. In other words, pretend to go to a hospital, or even go there in reallity, where a medical staff would flush this liquid in a toilet, but thus pretending to have injected it into your body.... and then, after some time, you'll receive a real certificate. All is legal. The only difference is︀ that that an experimental liquid was flushed in the toilet instead of being injected into︁ your body.
2) Get some certificate that you're exempt. It's easier to get it, and︂ less illegal, I'd imagine.