Antimicrobial Prophylaxis after Tick Bites

To the Editor: We believe Shapiro et al. (Dec. 17 issue)¹ had inadequate evidence to support their recommendation for nontreatment of deer-tick bites. The population samples were much too small for a meaningful comparison of the risks of serious late sequelae with the risks and benefits of prophylactic antibiotic therapy. Consider the hypothetical situation of 10,000 deer-tick bites in Connecticut, in which 120 people would acquire the disease and 15 to 36 would not manifest erythema migrans. Magid et al.² estimate that 60 percent of these people would acquire chronic arthritis, 17 percent meningoencephalitis or neuropathy, and 6 percent cardiac…