Antibiotic prophylaxis with a single dose of doxycycline after a tick bite is one of the tools for preventing Lyme disease, which is becoming increasingly prevalent in Quebec. The aim of this work was to revisit this practice in adults and children younger than 8 years of age.

To assess the safety and absolute risk reduction (ARR) of doxycycline for preventing Lyme disease in contraindicated populations, two systematic reviews were conducted with a re-analysis of the original efficacy data. A knowledge mobilization framework was used to consider the scientific, contextual, and experiential evidence, taking into account information on patients’ and clinicians’ experiences.

A single dose of doxycycline prescribed within 72 hours of being bitten by a tick (Ixodes scapularis) could prevent cutaneous manifestation of Lyme disease (ARR -2.8%, 95% confidence interval: -11.7–6.1; p = 0.06), without serious side effects, provided that the bite occurred in a geographical region where at least 25 percent of nymph and 50 percent of adult ticks are infected with the disease. However, the level of evidence was low and its generalizability to other contexts was doubtful. The decision to prescribe antibiotic prophylaxis may be based more on the fear of Lyme disease, rather than on effectiveness data and the real risk of contracting Lyme disease.

It may be challenging for clinicians to discuss Lyme disease prophylaxis with patients and their families in contexts where people are fearful of the disease, and the risk of contracting it from a tick bite is uncertain. Decision aids that provide scientific evidence on the real risk of developing Lyme disease after a tick bite, particularly in Quebec, can promote informed decisions based on patient preferences and values by supporting discussion between clinicians and patients.