Which trial do we need? Doxycycline vs. doxycycline-hydroxychloroquine and treatment duration protocol for Q fever endovascular infections

Chronic Q fever includes mainly endocarditis and other endovascular infections and more rarely osteoarticular infections. Treatment for the various manifestations of chronic Q fever has been standardized in the last 20 years to doxycycline and hydroxychloroquine given for a minimum of 18 to 24 months. 1 Anderson A. Bijlmer H. Fournier P.E. et al. Diagnosis and management of Q fever--United States, 2013: recommendations from CDC and the Q Fever Working Group. MMWR Recomm Rep. 2013; 62: 1-30 PubMed Google Scholar ,2 Raoult D 2019. DIAGNOSTIC ET TRAITEMENT FIEVRE Q. https://www.mediterranee-infection.com/wp-content/uploads/2019/08/Protocoles-FQ-franc%CC%A7ais-23-AOUT-2019-Anatomy-Bacteriology-OKDR.pdf. Google Scholar Recommendations on duration of treatment beyond the minimal period are based mostly on levels of Q fever IgG phase 1 titers. Monitoring of drug levels is recommended by some experts.