IMPACT OF COVID-19 ON TUBERCULOSIS CASE DETECTION IN VIET NAM: A MODELLING ANALYSIS

Background Viet Nam, a high-burden tuberculosis (TB) country, observed marked declines in TB notifications during the COVID-19 pandemic. We sought to determine whether and how COVID-19-related factors have influenced TB transmission and control, as well as their long-term effects, aiming to inform and enhance TB control strategies. Methods We developed a compartmental TB transmission model to estimate COVID-19's impact on TB detection and transmission in Vietnam. We simulated future scenarios to evaluate the potential benefits of enhanced TB case detection. Results The COVID-19 pandemic significantly impacted TB control in Viet Nam, leading to a sharp decline in case detection in 2021. This resulted in approximately 1,900 new TB episodes (95% credible interval [CrI]: 200 - 5,100) and 1,100 TB-related deaths (95% CrI: 100 - 2,700) in that year. Projections suggest that by 2035, these disruptions could contribute to 22,000 additional TB episodes (95% CrI: 1,900 - 63,000) and 5,900 more deaths (95% CrI: 600 - 16,600). We predicted two hypothetical scenarios of enhancing TB case detection. Under the ambitious scenario, enhancing TB case detection could mitigate these potential impacts by preventing 17.8% of new TB episodes (95%CrI: 13.1% - 21.9%) and 34.2% (95%CrI: 31.5% - 37.0%) of TB-related deaths by 2035, compared to no enhancement. Conclusions COVID-19 disruptions have created a backlog of undiagnosed TB cases, increasing transmission and mortality. Sustained investment in diagnostics, healthcare resilience, and proactive policies is essential to mitigate long-term consequences.