The potential impact of novel tuberculosis vaccines on health equity and financial protection in low- and middle-income countries

Background: One in two patients developing tuberculosis (TB) in low- and middle-income countries (LMICs) faces catastrophic household costs. We assessed the potential financial risk protection from introducing novel TB vaccines, and how health and economic benefits would be distributed across income quintiles. Methods: We modelled the impact of introducing TB vaccines meeting the WHO preferred product characteristics in 105 LMICs. For each country, we assessed the distribution of health gains, patient costs, and household financial vulnerability following introduction of an infant vaccine, and separately for an adolescent/adult vaccine, compared to a 'no-new-vaccine' counterfactual. Patient-incurred direct and indirect costs of TB disease exceeding 20% of annual household income were defined as catastrophic. Findings: Over 2028-2050, the health gains resulting from vaccine introduction were greatest in lower income quintiles, with the poorest two quintiles in each country accounting for 56% of total LMIC TB cases averted. Over this period, the infant vaccine was estimated to avert $5.9 (95% uncertainty interval: $5.3-6.5) billion in patient-incurred total costs, and the adolescent/adult vaccine was estimated to avert $38.9 ($36.6-41.5) billion. Over this period, 3.7 (3.3-4.1) million fewer households were projected to face catastrophic costs with the infant vaccine, and 22.9 (21.4-24.5) million with the adolescent/adult vaccine, with 66% of these gains accruing in the poorest two income quintiles. Interpretation: Under a range of assumptions, introducing novel TB vaccines would reduce income-based inequalities in the health and household economic outcomes of TB in LMICs.