COVID-19 setbacks threaten Vietnam's fight against tuberculosis

Vietnam is one of the countries with a high burden of tuberculosis (TB), and the COVID-19 pandemic coincided with large drops in the number of people reported with TB. To understand what those drops might mean for actual infections and deaths, Long Viet Bui and colleagues used a mathematical model that represents TB transmission across ages and stages of disease. The team calibrated this age-structured compartmental TB transmission model to local demographic and epidemiological observations so it would reflect Vietnam’s population and recent TB data. They considered four different assumptions about how the pandemic might have changed TB detection and transmission, and fit those possibilities to recorded TB notifications to see which matched reality best. The chosen model was then used to project future TB cases and deaths and to examine what would happen under hypothetical programs that improve TB case detection after the pandemic. By tying the model closely to observed notification changes, the researchers aimed to estimate both the immediate impact of COVID-19 on TB services and the longer-term consequences for transmission across the country.

The analysis used the best-fitting model assumption to estimate how disruptions during COVID-19 affected TB in Vietnam. The researchers concluded that services were significantly disrupted in 2021, estimating about 2,000 additional TB episodes (95% credible interval [CrI]: 200-5,100) and around 1,100 TB-related deaths (95%CrI: 100-2,700) in that year alone. Looking further ahead, the model projected the cumulative impact of these disruptions could reach roughly 22,000 additional TB episodes (95%CrI: 2,200-63,000) and 5,900 additional deaths (95%CrI: 600-16,600) by 2035. The team also modelled two hypothetical scenarios in which TB case detection was enhanced after the pandemic; under the most ambitious scenario, improved case detection could prevent 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 with taking no additional detection actions.

These findings suggest that interruptions to TB detection during COVID-19 likely produced not only an immediate shortfall in diagnosed cases but also a lasting rise in transmission and deaths unless countermeasures are taken. The authors emphasise that uncertainty around the size of these effects is considerable—the credible intervals are wide—so the exact toll remains unclear. Still, the model shows a clear direction: improving case finding and restoring TB services can meaningfully reduce the extra burden caused by the pandemic. The study highlights the potential value of sustained investment in diagnostics, strengthening system resilience to future shocks, and adopting patient-centric policies to find and treat people with TB. In short, recovery efforts that prioritise active case detection and robust TB programs could produce benefits substantially larger than the pandemic-related setbacks the model describes.