Tuberculosis: a biosocial problem that requires biosocial solutions

Even in countries such as Canada with a low tuberculosis burden, the average annual rates of tuberculosis can be 290 times higher in vulnerable populations such as Inuit communities compared with Canadian-born, non-Indigenous people.5 To accelerate the decline of the incidence and mortality of this biosocial disease and mitigate its socioeconomic impacts, optimal and equitable use of existing biomedical interventions needs to be scaled up together with public health and socioeconomic solutions.6 The biomedical armamentarium (panel) to reduce tuberculosis incidence includes the BCG vaccine, which is protective against severe forms of childhood tuberculosis, and tuberculosis preventive treatment (TPT), which now aims to cover other household contacts and clinical risk groups apart from children younger than 5 years and household contacts with HIV.7 Newer, shorter course (1–3 month) and effective rifamycin-based regimes are available and need to be scaled up.7 Between 2018 and 2022, the global target of TPT coverage in people living with HIV was achieved, but coverage in other populations was still inadequate or even poor (55% of children younger than 5 years and 10% of contacts older than 5 years).8 Expanded uptake of TPT will require increased awareness of its importance in communities and front-line providers, improved availability and affordability of newer, shorter regimens, and strengthened primary health care as a cornerstone of UHC.9 In parallel, tuberculosis incidence can be reduced by actions (panel) to address major risk factors for tuberculosis such as malnutrition and food insecurity, which are worsening due to the impacts of the COVID-19 crisis, conflicts, economic downturns, growing inequality, and the climate crisis.10 Undernutrition is a leading risk factor for tuberculosis incidence, accounting annually for 2·2 million cases globally and 34–45% of incident cases in India, the world's highest tuberculosis burden country.4,11 Yet some optimism for ways to reduce tuberculosis incidence can be found in the results of the RATIONS trial from India, which showed that nutritional supplementation in household contacts could reduce tuberculosis incidence by 40–50%.12 Nutrition could complement TPT in communities with severe prevalence of undernutrition.12 Indeed, modelling suggests that action on poverty and expanding social protection could reduce tuberculosis incidence by 84%.13 Alongside such strategies, accelerated action is needed to reduce tuber