Close, the current operant theory is introducing dead (or mostly dead) viruses into yourself.
This is hoped that the body will recognize it as foreign and then make antibodies against it.

Basically, telling your body, when you see this thing, kill it.

(a virus is RNA, it is not a full cell, so not DNA)

The current way to "grow" (multiply) viruses is to inject them into a mouse.
Let the mouse get all sick and grow lots of viruses.
Then suck them out (along with the blood)

So, the least you are getting when you get a vaccine shot is some mouse tissue injected into you.

Now, the problem with the Wuhan-flu is that it doesn't seem to be building an immunity.
People are getting it a second time. (there are various theories on this)

Just like many other viruses (like hepatitis) there is no vaccine.
Because the body doesn't create an immunity against the disease.

So a different method has to be found.

With the Wuhan-flu it appears that having an ultra-high vitamin C level is proof against the disease.