‘30 years of SHIELD’ – an overview and update on surveillance of occupational asthma in the West Midlands, United Kingdom

SHIELD is a voluntary reporting & surveillance scheme for occupational asthma (OA) for respiratory/occupational physicians in West Midlands, UK. Since 1989 it has provided in-depth data on OA cases and workplace outbreaks. Previous publications have reported data from 1991-2011. We retrospectively reviewed the SHIELD database (1991-2021), to measure occurrences and trends in reporting and causative agents. We also describe data from 2011-2021. 2776 patients were reported to SHIELD between 1991-2021. Total cases reported annually was variable (26-214), with average of 89.5 cases per year. Figure 1 demonstrates the trends in causative agents for 1991-2021. <fig><object-id>erj;64/suppl_68/PA3116/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> The top cause continued to be isocyanates; 19% in 1991-2001, 26% in 2001-2011, 23% in 2011-2021. For 2011-2021; at diagnosis 17% had prior asthma diagnosis and 41% had positive skin prick or positive specific IgE. 91% had symptom improvement on weekends and 95% on holidays. The majority of cases (95%) used history and serial PEFs to aid diagnosis. 53% of patients had a non-specific challenge test while exposed and 20% when unexposed, and 8% had a specific inhalation challenge. Causative agent and objective testing methods have varied over 30 years. Future work will better align coding of causative agents as well as digitising submission tools for improved analysis.