Response to Commentary Promoting the New Lyme Disease Guidelines

Repeating incorrect information does not cause it to become correct. The erroneous statement by Auwaerter et al, that taking single-dose doxycycline after an Ixodes tick bite prevents Lyme disease, has not been demonstrated by any North American study to date. Although repeatedly cited as demonstrating this, the 2001 Nadelman study did not follow its subjects long enough to demonstrate this point. It is well known that later manifestations of Lyme disease may develop beyond the 6-week follow-up period used by the investigators. The study's wide confidence intervals make even its stated 87% efficacy at preventing rash at the site of tick bite a likely overestimate. This is the only North American single-dose doxycycline study cited by the updated guideline discussed by Auwaerter et al. European studies, having different vectors and pathogens, are uninformative. A more valid assessment of the current science is that the optimum dosage and duration of antibiotic prophylaxis for preventing Lyme disease after an Ixodes tick bite remains unknown. If the uncertainty is acknowledged, perhaps investigators will study different dosages and durations, following patients long enough to make this determination. When we do not point out the strengths and limitations of available information, clinicians, who manage uncertainty every day in their practices, may have the quality of their decision-making diminished and their patients subject to undisclosed risks.