Impact of tuberculosis healthcare service disruptions during and after the COVID-19 pandemic in South Africa—a mathematical modelling study

Background The COVID-19 pandemic disrupted essential healthcare services globally, including tuberculosis care. These disruptions impaired tuberculosis diagnosis and treatment, but their long-term impact remains unclear. We aimed to estimate excess incident tuberculosis cases and deaths through 2035 attributable to pandemic-related disruptions and assess implications of delayed recovery and future disruptions. Methods We developed a compartmental, transmission-dynamic model of tuberculosis in South Africa, calibrated to demographic and epidemiological data. Disruptions were modelled as reduced healthcare seeking and increased unfavourable treatment outcomes, informed by programme and laboratory time-series data. We simulated four scenarios reflecting varying durations of recovery and additional disruptions: (1) full service recovery to pre-pandemic levels by 2022; (2) disruptions persisting through 2025; (3) through 2035; and (4) through 2025, followed by heightened disruptions (75% of 2020 levels) until 2030, with partial recovery thereafter. Primary outcomes were excess tuberculosis cases and deaths, 2020–2035. Findings We estimated 29,900 (95% uncertainty interval [UI]): 10,400–55200) excess tuberculosis cases and 12,400 (95% UI: 7500–19,300) deaths in 2020–2035, attributable to disruptions during 2020–2021. Assuming full recovery from 2022, 48% (95% UI: 35–57) of excess cases and 19% (95% UI: 8.3–31) of deaths will occur between 2026 and 2035. Disruptions persisting through 2025 could double this burden. Under heightened disruption during 2025–2030, excess cases and deaths could increase sixfold. Delayed diagnosis was the main driver of the excess burden. Interpretation Pandemic-related disruptions have caused a substantial excess tuberculosis burden. Its long-term trajectory will depend on the pace of recovery and resilience to future disruptions. Funding South African Medical Research Council (https://www.samrc.ac.za/) via BRICS STI Framework Programme.