To the Editor:
Repeating incorrect information does not cause it to become correct. The erroneous statement by Auwaerter et al,
1
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 study2
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.3
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 guideline4
discussed by Auwaerter et al.1
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.References
Auwaerter PG, Kobayashi T, Wormser GP. Guidelines for Lyme disease are updated [e-pub ahead of print]. Am J Med. doi: 10.1016/j.amjmed.2021.06.051, Accessed August 10, 2021.
- Prophylaxis with single-dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite.N Engl J Med. 2001; 345: 79-84
- The management of Ixodes scapularis bites in the upper Midwest.WMJ. 2011; 110 (quiz 85): 78-81
- Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR): 2020 Guidelines for the Prevention, Diagnosis, and Treatment of Lyme Disease.Arthritis Rheumatol. 2021; 73: 12-20https://doi.org/10.1002/art.41562
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