The Qure Study: Q-fever Fatigue Syndrome - Response to Treatment

Inclusion Criteria: * Males or non-pregnant, non-lactating females who are 18 years or older * Laboratory-proven acute Q fever since the year 2007 and/or positive serology fitting a past infection with Coxiella burnetii; * AND being severely fatigued, defined by scoring 35 or higher on the subscale fatigue severity of the CIS; * AND being fatigued for at least 6 months; * AND disabled because of the fatigue, defined by scoring 450 or higher on the SIP * Subjects must sign a written informed consent form. Exclusion Criteria: * Fulfilling criteria for chronic Q fever, namely: * IFA IgG fase I ≥ 1024, ≥ 3 months after acute Q fever and/or * Positive Coxiella burnetii PCR on serum or tissue, 1 month after acute Q fever * Acute Q fever in the setting of a prosthetic cardiac valve or aneurysm surgery or stenting necessitating prophylactic use of doxycycline; * Pregnancy or unwillingness to use effective contraceptives during the entire study period; * Imminent death; * Inability to give informed consent; * Allergy or intolerance to doxycycline; * Somatic or psychiatric illness that could explain the chronic fatigue; * Subjects who are currently enrolled on other investigational drug trials or receiving investigational agents; * Receiving antibiotics for more than 4 weeks, potentially active against Coxiella burnetii, for any other reason since Q-fever diagnosis; * Subjects who are receiving and cannot discontinue barbiturates, phenytoin, or carbamazepine (these drugs may increase the metabolism of doxycycline and therefore reducing half-life of doxycycline); * Moderate or severe liver disease (AF, ALAT, ASAT \> 3 times the upper limit of normal). * Current engagement in a legal procedure concerning financial benefits (only current involvement interferes with the effectivity of cognitive behavioral therapy. Once the appeal procedure ends, subjects can be included)