A prolonged outbreak of tuberculosis associated with an intellectual disability daycentre in Ireland

Abstract One of the factors impeding tuberculosis elimination in low burden countries is its persistence and concentration in vulnerable populations. This is a complex, prolonged Tuberculosis (TB) outbreak in a daycentre for adults with intellectual disability in Ireland. This is a particularly vulnerable population with special considerations for Public Health (PH) management. There are eight cases of active TB, 46 cases of Latent TB Infection (LTBI) and a cumulative total of 116 contacts associated with this outbreak, with diagnosis spanning 15 years. The last three cases were identical on Whole Genome Sequencing. The index case was an Irish-born, Caucasian, social care worker, with smear positive pulmonary TB, who was symptomatic in the facility for three months prior to diagnosis. Case 2 was a household contact of the index case and the other 6 cases were Service Users (SUs) at the facility. At least five of the subsequent seven cases are secondary cases of the index case. Significant to this outbreak was the change in Irish guidance, 2010, relating to the management of contacts of cases. Following the notification of the most recent case, July 2023, the Outbreak Control Team decided a retrospective review be conducted of all SU contacts of the seven cases associated with the facility. The contacts were stratified according to hierarchical risk. A total of six contacts met the criteria for review and offered screening, re-screening or treatment as appropriate. In this outbreak 21.8% of the total contacts and 16.1% of SU contacts completed treatment for LTBI. The significance of this outbreak lies in its duration, infectivity of the index case and particular vulnerabilities of the SUs. There were issues with overcrowding and difficulties in relation to symptom recognition, diagnosis and treatment. The PH team tailored their approach to meet the SU needs, demonstrating the importance of person-centred contact tracing in the disruption of transmission. Key messages • A factor impeding tuberculosis elimination in low burden countries is it’s persistence and concentration in vulnerable populations. • Adapting a patient-centred approach to contact tracing can lead to higher participation rate and the disruption of infection transmission.