Prevalence, incidence and determinants of quantiferon-positivity in south african schoolchildren

Background: Tuberculosis (TB) control requires the understanding and disruption of TB transmission. We describe prevalence, incidence and risk factors associated with childhood TB infection in Cape Town. Methods: We report cross-sectional baseline and prospective incidence data from a large trial among primary school children living in high TB-burden communities. Prevalent infection was defined as QuantiFERON-TB Gold Plus (QFT-Plus) positivity as assessed at baseline. Subsequent conversion to QFT-Plus positivity was measured 3 years later among those QFT-Plus-negative at baseline. Multivariable logistic regression models examined factors associated with TB infection. Results: QuantiFERON-positivity at baseline (prevalence: 22.6%, 95% Confidence Interval [CI]: 20.9 - 24.4), was independently associated with increasing age (adjusted odds ratio [aOR] 1.24 per additional year, 95% CI: 1.15 - 1.34) and household exposure to TB during the participant's lifetime (aOR 1.87, 95% CI: 1.46 - 2.40). QFT-Plus conversion at year 3 (12.2%, 95% CI: 10.5-14.0; annual infection rate: 3.95%) was associated with household exposure to an index TB case (aOR 2.74, 95% CI: 1.05 to 7.18). Conclusion: Rates of QFT-diagnosed TB infection remain high in this population. The strong association with household TB exposure reinforces the importance of contact tracing, preventative treatment and early treatment of infectious disease to reduce community transmission. ### Competing Interest Statement ARM declares receipt of funding in the last 36 months to support vitamin D research from the following companies who manufacture or sell vitamin D supplements: Pharma Nord Ltd, DSM Nutritional Products Ltd, Thornton & Ross Ltd and Hyphens Pharma Ltd. ARM also declares receipt of vitamin D capsules for clinical trial use from Pharma Nord Ltd, Synergy Biologics Ltd and Cytoplan Ltd; support for attending meetings from Pharma Nord Ltd and Abiogen Pharma Ltd; receipt of consultancy fees from DSM Nutritional Products Ltd and Qiagen Ltd; receipt of a speaker fee from the Linus Pauling Institute; participation on Data and Safety Monitoring Boards for the VITALITY trial (Vitamin D for Adolescents with HIV to reduce musculoskeletal morbidity and immunopathology, Pan African Clinical Trials Registry ref PACTR20200989766029) and the Trial of Vitamin D and Zinc Supplementation for Improving Treatment Outcomes Among COVID-19 Patients in India (ClinicalTrials.gov ref [NCT04641195][1]); and unpaid work as a Programme Committee member for the Vitamin D Workshop. All other authors declare that they have no competing interests. ### Clinical Trial NCT02880982 ### Funding Statement This research was funded by the UK Medical Research Council (refs MR/R023050/1 and MR/M026639/1, both awarded to ARM). RJW was supported by Wellcome (104803, 203135). He also receives support from the Francis Crick Institute which is funded by Cancer Research UK (FC2112), the UK Medical Research Council (FC2112) and Wellcome (FC2112). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/IRB of University of Cape Town Faculty of Health Sciences gave ethical approval for this work Observational/Interventions Research Ethics committee/IRB of London School of Hygiene and Tropical Medicine gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Anonymised data may be requested from the corresponding author to be shared subject to terms of research ethics committee approval. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT04641195&atom=%2Fmedrxiv%2Fearly%2F2024%2F03%2F13%2F2024.03.11.24304073.atom