Cost-effectiveness modelling studies of all preventive measures against rabies: A systematic review

Rabies is one of the most feared infectious diseases worldwide, predominantly occurring in Asia and Africa where rabies is endemic in domestic dog populations. Whereas previous studies have demonstrated mass dog vaccination and post-exposure prophylaxis (PEP) as the most effective control strategies, successful rabies elimination has yet to be realized as these recognized effective interventions continue to face challenges of limited accessibility. In the light of new evidence towards improving programmatic feasibility and clinical practice in rabies control especially among endemic countries, a systematic review was undertaken to identify cost-effectiveness modelling studies of rabies preventive measures and to provide a critical review of published evidence through comparative evaluation and model quality assessment, and a synthesis of key findings based thereon. Our search through MEDLINE and SCOPUS identified a total of 17 studies which mostly focused on estimating the impact of increasing PEP and pre-exposure prophylaxis (PrEP) access, human rabies elimination scenarios using mass dog vaccinations only or complemented with PEP strategy. While no significant methodological inconsistency across studies was identified and the extent of reporting is generally high, we note several points for quality and internal validity improvement. Assessment of modelling approach showed that decision tree models had similar pathways. The results of the studies suggest that interventions would be cost-effective at the cost-effectiveness threshold of 1 to 3 times per capita Gross Domestic Product (GDP) as recommended by the Commission on Macroeconomics and Health's GDP based thresholds, compared with no intervention in rabies endemic countries. When compared across studies which reported incremental cost-effectiveness ratio (ICER) as cost per QALY gained or DALY averted in international dollars adjusted by purchasing power parity conversion rate, PEP vaccination yields less cost per DALY averted or QALY gained due to one year-horizon assessment compared to canine vaccination at 4- or 10-year-time horizon.