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. Funding World Health Organization (2020/985800-0) Evidence before this study We searched MEDLINE using the terms “tuberculosis,” “catastrophic cost*,” and “vaccin*” and failed to find any original research articles that estimated the impact of TB vaccination on catastrophic costs incurred by TB patients. Previous studies have shown that improved TB prevention and care can lower patient costs and reduce the number of TB-affected households experiencing catastrophic costs, and previous modelling has estimated the potential impact of TB vaccination on patient costs in country case-studies. Survey evidence from high-burden countries have consistently demonstrated higher disease burden among poorer individuals, with TB prevalence in the lowest income quintile on average 2·3 times greater than estimated for the highest income quintile. TB patient cost surveys in high-burden countries have shown that TB patients experience high out-of-pocket and indirect costs, and that these costs represent a greater share of annual household income in poorer income quintiles. Added value of this study This is the first study to examine the potential for new vaccines to reduce the number of households experiencing catastrophic costs due to TB, and how both these benefits and health gains are distributed across income quintiles. Across all modelled countries over 2028–2050, an adolescent/adult vaccine was projected to reduce TB incidence in the poorest quintile by 13·3 (10·9–15·8) million (30% of total TB cases averted) and reduce the number of households experiencing catastrophic costs by 9·2 (7·5–11·0) million in the poorest quintile (40% of total cases of catastrophic costs averted) compared to the no-new-vaccination baseline. Implications of all the available evidence Under a range of assumptions, new TB vaccines could be highly impactful and help narrow income-based disparities in the health and the economic consequences of TB for low- and middle-income countries. ### Competing Interest Statement RAC is funded by BMGF (INV-001754) and received a grant from the Canadian Centennial Scholarship Fund. CKW is funded by UKRI/MRC (MR/N013638/1). RGW is funded by the Wellcome Trust (218261/Z/19/Z), NIH (1R01AI147321-01), EDTCP (RIA208D-2505B), UK MRC (CCF17-7779 via SET Bloomsbury), ESRC (ES/P008011/1), BMGF (OPP1084276, OPP1135288 & INV-001754), and the WHO (2020/985800-0). All other authors declare no conflicts of interest. ### Funding Statement This study was funded by World Health Organization (2020/985800-0). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.