ABSTRACT
BACKGROUND: Most paediatric tuberculosis (TB) cases in low-TB-incidence countries involve children born to migrant families. This may be partially explained by trips to their countries of origin for visiting friends and relatives (VFR). We aimed to estimate the risk of latent TB infection (LTBI) and TB in children VFR. METHODS: We conducted a prospective multicentric observational study in Catalonia (Spain) from 06/2017 to 12/2019. We enrolled children aged < 15 years with a negative tuberculin skin test (TST) at baseline and at least one parent from a high-TB-incidence country, and who had travelled to their parent's birth country for ≥21 days. TST and QuantiFERON-TB Gold Plus (QFT-Plus) were performed within 8-12 weeks post-return. LTBI was defined as a TST ≥5 mm and/or a positive QFT-Plus. RESULTS: Five hundred children completed the study, equivalent to 78.2 person-years of follow-up (PYFU). Thirteen children (2.6%) were diagnosed with LTBI (16.6/per100 PYFU,95%CI = 8.8-28.5), including two cases (0.4%) of TB (2.5/per100 PYFU, 95%CI = 0.3-9.3). LTBI incidence rates remained high after excluding BCG-vaccinated children (9.7/per100 PYFU,95%CI = 3.9-20.0). Household tobacco smoke exposure was associated with LTBI (aOR = 3.9, 95%CI = 1.1-13.3). CONCLUSIONS: The risk of LTBI in children VFR in high-TB-incidence countries may equal, or perhaps even exceed, the infection risk of the native population. The primary associated risk factor was the presence of smokers in the household. Furthermore, the incidence rate of active TB largely surpassed that of the countries visited. Children VFR in high-TB-incidence countries should be targeted for diagnostic and preventive interventions.
ABSTRACT
INTRODUCTION: Tuberculosis (TB) is a global infectious disease. In low-incidence countries, paediatric TB affects mostly immigrant children and children of immigrants. We hypothesize that these children are at risk of exposure to Mycobacterium tuberculosis when they travel to the country of origin of their parents to visit friends and relatives (VFR). In this study, we aim to estimate the incidence rate and risk factors associated to latent tuberculosis infection (LTBI) and TB in VFR children. METHODS AND ANALYSIS: A prospective study will be carried out in collaboration with 21 primary health care centres (PCC) and 5 hospitals in Catalonia, Spain. The study participants are children under 15 years of age, either immigrant themselves or born to immigrant parents, who travel to countries with high incidence of TB (≥ 40âcases/100,000 inhabitants). A sample size of 492 children was calculated. Participants will be recruited before traveling, either during a visit to a travel clinic or to their PCC, where a questionnaire including sociodemographic, epidemiological and clinical data will be completed, and a tuberculin skin test (TST) will be performed and read after 48 to 72âhours; patients with a positive TST at baseline will be excluded. A visit will be scheduled eight to twelve-weeks after their return to perform a TST and a QuantiFERON-TB Gold Plus test. The incidence rate of LTBI will be estimated per individual/month and person/year per country visited, and also by age-group. ETHICS AND DISSEMINATION: The study protocol was approved by the Clinical Research Ethics Committee of the Hospital Universitari Mútua Terrassa (code 02/16) and the Clinical Research Ethics Committee of the Fundació Institut Universitari per a la Recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (code P16/094). Articles will be published in indexed scientific journals. TRIAL REGISTRATION: Clinical-Trials.gov: NCT04236765.
