SPECIFIC ISSUES IN THE DESIGN AND IMPLEMENTATION OF AN EFFICACY TRIALFOR A LYME-DISEASE VACCINE

Lyme disease is an emerging infection that has now become the most com monly reported vector-borne disease in the United States. In the 20 ye ars since its initial description, scientific and technological advanc es have led to candidate vaccines for the prevention of Lyme disease. Recombinant outer surface protein A (OspA) vaccines have been successf ul in protecting mice in tick-challenge experiments. A candidate OspA vaccine has been found to be safe acid immunogenic in phase I and II s tudies. This article describes some of the lessons that were learned a nd some of the unique obstacles encountered in the design and implemen tation of a large phase III efficacy field trial. Pivotal trials of va ccines for Lyme disease can be a major investment of time and resource s for subjects, investigators, and sponsors. If properly conducted, th ey also present unique opportunities to expand our knowledge of the di sease.