There are many strains. You will develop immunity to one strain, but not the others.

I assume a vaccine would try to be multivalent.

Even for the specific strain, it's not long-lived and strong enough.

“Lyme” colloquially covers half a dozen to a dozen different bacterial infections.

"Lymne" refers to an infection by the spirochete Borrelia burgdorferi, a bacteria closely related to syphillis. There are plenty of other tick-borne diseases (including localized staph infections at bite sites that can lead to necrotizing fasciitis)

Just like with syphillis, there is a cheap and simple cure that is more effective than any known vaccine. If it's caught in time. Prevention is even cheaper.

The standard treatment for Lyme also just happens to be the standard treatment for many of the other tick-borne diseases, so you're still better-off taking a course of doxycycline after a tick byte than getting a vaccination against Lyme.

> Lymne" refers to an infection by the spirochete Borrelia burgdorferi

There are also common coinfections which are grouped under the same name, despite being unique.

IIRC there's no immunity. Or at least it's gone after some time.