2007, Jule Klotter, “Jarisch-Herxheimer reactions”, in Townsend Letter: The Examiner of Alternative Medicine, volume 285, page 48:
JHR, or “Herx,” as some patients call it, is a worsening of condition that occurs shortly after the first adequate dose of an appropriate antimicrobial therapy. This reaction has been observed in many bacterial infections and in some protozoal infections.
2019 July 22, Molly Fischer, “Maybe it’s Lyme”, in New York magazine:
Herxes, or “herxing,” are a great bugbear in the world of chronic Lyme. The term is drawn from the Jarisch-Herxheimer reaction, originally identified in the context of syphilis. It refers to a brief, severe reaction that can take place within the first few days of antibiotic treatment; as bacteria die off and release endotoxins, a patient experiences fever, chills, and sometimes dangerously low blood pressure.
2022 March 21, Gregory Derderian, “A Small Cohort of Patients with Post Treatment Lyme Disease Syndrome Treated with HIFEM”, in SSRN[1]:
During the course of using a HIFEM device for cosmetic treatment, a direct effect on two patients was noted, each with Post Lyme Disease Syndrome (PTLDS) and each demonstrating a Jarisch-Herxheimer (Herx) reaction post treatment. A Herx reaction is due to endotoxin-like products released by the death of Borrelia Burgdorferi within the body, during antibiotic treatment, indicating efficacious antimicrobial therapy.
