The present invention relates to compositions useful in the prevention and treatment of a Borrelia infection. Particularly, the present invention relates to an immunogenic polypeptide comprising a hybrid C-terminal fragment of an outer surface protein A (OspA), a nucleic acid coding the same, a host cell comprising the nucleic acid, a method for producing the polypeptide, a pharmaceutical composition comprising the polypeptide or nucleic acid, particularly for use as a medicament or vaccine or for use in a method of treating or preventing a Borrelia infection.