An analysis of factors contributing to excess US tuberculosis (TB) cases and deaths from the onset of the COVID-19 pandemic in 2020 and projections up to 2035 estimates nearly 3,000 more cases and more than 1,100 TB deaths than expected.
A team led by Harvard University researchers identified four mechanisms that may have contributed to TB trends from 2020 to 2023: immigration, respiratory contact rates, rates of accurate diagnosis and treatment initiation, and death rates for TB patients. The researchers used a Bayesian approach to synthesize evidence on mechanism changes during the pandemic and how they might have combined to produce the observed TB trends.
They also simulated a no-pandemic counterfactual scenario that assumed that mechanisms followed prepandemic patterns, estimated TB outcomes tied to the pandemic until 2035 to capture lagged effects, and assessed other scenarios to estimate the effect of each mechanism.
TB “notifications and deaths in the United States fluctuated substantially during the coronavirus disease 2019 (COVID-19) pandemic,” the study authors wrote. “We analyzed multiple data sources to understand the factors contributing to these changes and estimated future TB trends.”
The findings were published late last week in Clinical Infectious Diseases.
Factors may continue to influence TB trends over time
From 2020 to 2035, the team estimated 2,784 excess TB cases and 1,138 deaths in the United States linked to changes occurring during the pandemic. Mechanisms had offsetting effects—decreases in TB diagnoses rates led to more TB deaths and notifications, while reductions in contact rates reduced TB deaths and notifications.
This study used mathematical modeling to explore the impact of COVID-19 pandemic on TB in the United States, finding increases in both TB notifications and TB deaths during 2020–2035.
Initially, immigration changes lowered TB deaths but raised deaths and notifications over time. Higher TB mortality rates increased TB deaths but decreased TB notifications.
“This study used mathematical modeling to explore the impact of COVID-19 pandemic on TB in the United States, finding increases in both TB notifications and TB deaths during 2020–2035,” the study authors concluded. “Although direct impacts of the COVID-19 pandemic occurred between 2020 and 2023, these changes may continue to influence TB incidence and mortality in future years.”