TB transmission [2]
A study investigates how TB spreads in urban Lima by analyzing over 2,500 culture-positive TB cases using whole-genome sequencing. Researchers assessed whether various demographic, social, and biological factors influence who transmits TB. They identified 1,447 direct transmission pairs based on genetic similarity and diagnosis timing.
Results showed that younger adults, males, smokers, and drinkers were more likely to be transmitters. Notably, incarceration history had a strong influence—if both individuals in a pair had been incarcerated, the likelihood of transmission increased over tenfold. Clinical features like cavitary disease and prior TB also raised the odds of transmission.
The study’s strength lies in using advanced genomic tools and a large cohort to clarify TB spread patterns in a community. These findings suggest that public health efforts should prioritize high-risk groups—especially former prisoners and substance users—to better curb TB transmission. Importantly, the study provides a template for using genomic data in real-world public health planning.
Smoking cessation in tuberculosis patients [1]
A study conducted in the metropolitan area of Lima, Peru, sought to investigate whether recent smoking cessation among pulmonary tuberculosis (TB) patients could reduce the risk of TB infection in their child household contacts compared to continued active smoking. Researchers enrolled newly diagnosed pulmonary TB patients and their household child contacts aged 15 years or younger between September 2009 and August 2012. At enrollment, patients' smoking histories were categorized as never smoked, distant quitters (ceased smoking more than two months prior to diagnosis), recent quitters (ceased smoking within two months of diagnosis), or active smokers. Tuberculosis infection among child contacts was assessed using the tuberculin skin test (TST) at baseline, six months, and twelve months.
The study population included 905 TB patients and 1811 child contacts, with 78% of the index patients classified as never smokers, 11.7% as distant quitters, 7.9% as recent quitters, and 2.5% as active smokers. At baseline, 24.4% of the child contacts tested TST-positive, a figure that rose to 37.3% by six months. Multivariate analysis showed that child contacts of recent quitters had a significantly lower risk of TB infection compared to those of active smokers, with adjusted risk ratios (aRR) of 0.45 at baseline and 0.48 at six months. Furthermore, the risk of infection among contacts of recent quitters was comparable to that among contacts of never smokers.
These findings suggest that children exposed to TB patients who had recently quit smoking had a significantly reduced risk of TB infection compared to those exposed to active smokers. Sensitivity analyses adjusting for disease severity, timing of quitting, and restricting to younger children confirmed the robustness of the results. Overall, the study highlights the potential for smoking cessation interventions to rapidly and effectively reduce TB transmission within households.
Source:
- Chu, A.L., Lecca, L.W., Calderón, R.I., Contreras, C.C., Yataco, R.M., Zhang, Z., Becerra, M.C., Murray, M.B. and Huang, C.C., 2021. Smoking cessation in tuberculosis patients and the risk of tuberculosis infection in child household contacts. Clinical Infectious Diseases, 73(8), pp.1500-1506.
- Trevisi, L., Brooks, M.B., Becerra, M.C., Calderón, R.I., Contreras, C.C., Galea, J.T., Jimenez, J., Lecca, L., Yataco, R.M., Tovar, X. and Zhang, Z., 2024. Who transmits tuberculosis to whom: a cross-sectional analysis of a cohort study in Lima, Peru. American Journal of Respiratory and Critical Care Medicine, 210(2), pp.222-233.
No comments:
Post a Comment