Tuberculosis Infection and Disease Among Pregnant People Living in Sweden With Origin in Tuberculosis-Endemic Countries

Abstract

Background Pregnancy has been associated with elevated incidence of tuberculosis disease. Since 2014, people living in Sweden with origin in tuberculosis-endemic countries are offered screening for tuberculosis infection in antenatal care (ANC) using Quantiferon-TB assays. We assessed factors associated with tuberculosis infection in this population, and determined the incidence of tuberculosis disease during pregnancy and postpartum periods with regard to ANC Quantiferon-TB results. Methods Quantiferon-TB results obtained during ANC in Sweden 2014-2018 were linked to data from national registers (Pregnancy Register, Patient Register and Tuberculosis Register). Factors associated with tuberculosis infection (defined as Quantiferon-TB ≥0.35 IU/ml) were identified using logistic regression analysis. Incidence of tuberculosis disease was determined with regard to pregnancy, post-partum and subsequent periods, and ANC Quantiferon-TB results. Results Among 7,638 screened individuals, 1,424 (18.6%) had tuberculosis infection. Tuberculosis infection was independently associated with higher age at immigration (adjusted odds ratio 1.04, 95% confidence interval 1.03–1.05; p < 0.001), and was more common among people originating from Africa compared to other world regions (845/3,088 [27.4%] vs. 579/4,550 [12.7%]; p < 0.001). In total, 16 participants were diagnosed with tuberculosis disease (10 during pregnancy, 4 < 6 months after delivery, 2 > 6 months after delivery); among these, all diagnosed during pregnancy/postpartum had positive ANC Quantiferon-TB results (constituting 14/1,424 [1%] of people with tuberculosis infection). Conclusions Among pregnant people screened in Swedish ANC, tuberculosis infection was associated with higher age and African origin. All cases of tuberculosis disease reported in persons with tuberculosis infection at ANC screening occurred during pregnancy or postpartum.