Cost-effectiveness of a Screening Strategy for Q Fever Among Pregnant Women in Risk Areas: a Clustered Randomized Controlled Trial

We will conduct a clustered randomized controlled trial among pregnant women within an area of high transmission. The study participants will be recruited by the midwives in high risk areas, defined by postal code from the RIVM. To inform the public in this area about the study we will publish an article in local newspapers. The midwife centers will be randomized to recruit pregnant women for either the control group or the intervention group. The pregnant women will receive study information by mail using the midwives patients file. It is estimated that approximately 10,000 eligible women live in the areas of transmission. After written informed consent, they will start with the strategy for which the midwife center is randomized.

Participants will be asked for a blood sample in their second trimester of pregnancy, possibly combined with the routine structural ultrasound around 20 weeks of pregnancy to minimize hospital visit. If participants are enrolled in their third trimester, they will have their blood sampling as soon as possible after inclusion.

When taking part in the intervention group the sample will be tested immediately for Q fever. If found positive for acute or chronic Q fever, patients have to be referred, according to local protocol, to a hospital for further pregnancy monitoring and long-term bacteriostatic treatment. Follow-up blood samples are required at 14 days, 3, 6 and 12 months after the first blood sampling as part of the standardized control of Q fever disease to diagnose possible chronicity of infection. Furthermore, current routine for pregnant women being treated with antibiotics against Q fever is to perform monthly blood analyses to monitor treatment, and if the serological parameters descend, these controls are brought back to once every two months. According to local protocol patients with Q fever have to deliver in hospital. After pregnancy serology should be continued with check-ups at 3, 6 and 12 months following the current protocol. Furthermore, after delivery a bacteriocide treatment with doxycycline or an alternative will be started by the specialist as part of regular health care.

In the control arm the blood samples will be stored, and analyzed for Q fever after delivery. If tested positive for Q fever after pregnancy antibiotics could be started if needed as part of regular health care.

At baseline, a questionnaire will be administered to all participants asking about the current pregnancy , pregnancy outcome of any previous pregnancies and demographics. Further risk factors for pregnancy outcome will also be obtained such as smoking and drinking behavior, risk-elevating comorbidities and medication use.