Background: Hepatitis D virus (HDV), which requires the presence of hepatitis B virus (HBV), is a deadly yet neglected disease that rapidly leads to liver cancer and disease-induced mortality. This co-dependence creates complex transmission dynamics that make it difficult to predict the efficacy of interventions aimed at HBV and/or HDV control in endemic regions, such as certain municipalities of Brazil, where up to 65% of HBV-infected persons are co-infected.
Methodology: We created a mathematical model that captures the joint transmission dynamics of HBV and HDV, incorporating mother-to-child, sexual and household transmission. With an aim to minimize the number of total infections and disease-induced mortality in 2027, we then determined optimal strategies for Brazil and its sub-regions under a constrained budget, which was dynamically allocated among HBV and HDV screening, HBV and HDV treatment, HBV newborn and adult vaccination, and awareness programs. Three treatment options were considered, namely: Tenofovir, PEGylated-Interferon, and nucleic acid polymers (NAP).
Results: The additional cost of HDV screening and the use of a more expensive PEGylated-Interferon are offset by not wasting resources on treating co-infected persons with Tenofovir. The introductory price of NAP treatment must be less than $16,000 per course to become competitive with Tenofovir and PEGylated-Interferon in Brazil.
Conclusion: Additional screening for HDV is beneficial, even in a low HBV and HDV endemic regions of Brazil. We recommend PEGylated-Interferon, wherever possible, for both HBV and HDV. If PEGylated-Interferon is not available in abundance, PEGylated-Interferon for co-infections and 4-year Tenofovir treatment for mono-infections is recommended.