Antigenic polypeptides comprising linear immunodominant epitopes of Borrelia outer surface protein A (OspA) or Borrelia outer surface protein C (OspC) are useful as vaccines against Lyme disease, and as diagnostics for detecting Borrelia infections. The OspA and OspC antigenic polypeptides typically comprise a plurality of peptides representing epitope containing regions from multiple distinct phyletic groups. The antigenic polypeptides may also include epitopes from both Borrelia OspA and Borrelia OspC.