The use of antibiotics as a prophylactic was found to be effective against Lyme disease, according to results of a meta-analysis published in BMC Infectious Diseases.
Investigators searched PubMed, Embase, and the Cochrane Library for studies which enrolled patients who had no clinical evidence of Lyme disease 72 hours after receiving a tick bite and were assigned to either the intervention or control groups. Patients in the intervention groups received either a 10-day course of oral antibiotics, a single 200-mg dose of oral doxycycline, or topical antibiotic treatment with azithromycin. A random-effects model was used to calculate the pooled results and the risk ratio for rates of unfavorable events among patients in both groups.
Overall, the final analysis included 6 randomized controlled trials with a total of 3766 patients, of whom 56 had unfavorable events. Of note, only 1 event was disseminated Lyme disease while 55 were erythema migrans.
Among patients in the intervention groups, the pooled rate of unfavorable events was 0.4% (95% CI, 0.1-1.1; I2 = 55%) vs 2.2% (95% CI, 1.6-3.0: I2 = 5%) among those in the control groups. In addition, the pooled risk ratio was 0.38 (95% CI, 0.22-0.66; I2 = 0%).
Among patients included in the 5 studies that assessed the effects of oral prophylactic antibiotics, the pooled rate of unfavorable events among those in intervention and control groups was 0.2% (95% CI, 0.0-1.0; I2 = 57%) and 2.5% (95% CI, 1.7-3.5; I2 = 0%), respectively, and the pooled risk ratio was 0.29 (95% CI, 0.15-0.57; I2 = 0%).
The pooled risk ratio for patients who received a single 200-mg dose of doxycycline and those who received a 10-day course of oral antibiotics was 0.29 (95% CI, 0.14-0.60; I2 = 0%) and 0.28 (95% CI, 0.05-1.67; I2 = 0%), respectively. Among patients who received topical antibiotics, the pooled risk ratio was 0.73 (95% CI, 0.25-2.08).
Study limitations included the small number of studies eligible for inclusion, the heterogeneity of tick species across study locations, and the use of erythema migrans as the primary endpoint for all included studies, which may have underestimated the actual incidence of Lyme disease.
According to the researchers, “the available evidence supports the prophylactic use of antibiotics for the prevention of Lyme disease and the advantages of a single dose of doxycycline, but further confirmation is needed.”
Zhou G, Xu X, Zhang Y, et al. Antibiotic prophylaxis for prevention against Lyme disease following tick bite: an updated systematic review and meta-analysis. BMC Infect Dis. 2021;21(1):1141. doi: 10.1186/s12879-021-06837-7.