The pharmaceutical companies Pfizer and Valneva have developed a jointly developed Lyme vaccine, PF-07307405, which is designed to prevent infections from Borrelia burgdorferi, the bacteria that causes Lyme disease. The vaccine was found to be more than 70% effective at preventing Lyme infection, although the underlying data was not as statistically robust as expected. The companies plan to submit the vaccine for FDA approval and are hopeful about its potential effectiveness. However, the primary analysis of the study’s data had a lower 95% confidence interval than the companies had hoped for. The potential effectiveness of the vaccine, which targets the six most common serotypes of B. burgdorFERi found in North America and Europe, is uncertain due to mild seasons leading to fewer cases of Lyme than expected during the study period.