Yes, Lyme disease itself is rarely fatal. However, in very rare cases, if left untreated, Lyme disease can lead to severe complications that may be fatal. One of the most serious complications is Lyme carditis, a heart condition caused by the infection, which can disrupt the heart's normal electrical signals and potentially cause sudden death if not treated promptly. Most fatalities from Lyme disease are related to untreated Lyme carditis. Early diagnosis and proper antibiotic treatment generally lead to full recovery and prevent fatal outcomes. In summary, while Lyme disease is usually not deadly and most people recover fully with treatment, untreated severe complications, especially involving the heart, can result in death in rare cases.