https://www.lymedisease.org/single-dose-doxy-tick-bite-prevents-rash-not-lyme-disease/  This link shows that Daniel J. Cameron, MD MPH, states there has only been one study (Nadelman et al) on the effectiveness of 1 pill of doxycycline and only found a reduction in the number of erythema migraines (EM) rashes compared to the placebo group.  According to him, the IDSA 1 pill of doxy approach started in 2006 despite the fact that three previous prophylactic antibiotic trials for a tick bite had failed.

http://www.jem-journal.com/article/S0736-4679(17)30026-4/abstract  However, the authors of this recent study in the Journal of Emergency Medicine support the 1 pill of doxy approach.  It fails to mention the ILADS approach where Lyme literate doctors with much experience treating Lyme/MSIDS advise against 1 pill of doxy and the reasons stated above by Cameron.

He also states that the evidence is easily accessible in open access, peer-reviewed journals in PubMed and the National Guideline Clearing House.

Cameron states:

“ILADS 2014 guidelines used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to conclude that the evidence for a single, 200 mg dose of doxycycline was “sparse, coming from a single study with few events, and, thus, imprecise.” 

 

According to Cameron Nadelman’s study had several other limitations:

“It was not designed to detect Lyme disease if the rash were absent.
The six-week observation period was not designed to detect chronic or late manifestations of Lyme disease.
It was not designed to assess whether a single dose of doxycycline might be effective for preventing other tick-borne illnesses such as Ehrlichia, Anaplasmosis, or Borrelia miyamotoi.”

Please spread the word and tell doctors.