Impact of the switch from four to three intradermal rabies post-exposure prophylaxis sessions in patients bitten by dogs: A cost-consequence analysis from the patients' perspective

The annual incidence of rabies deaths has been estimated in Cambodia at nearly 5.8/100,000 person-years. The cost of post exposure prophylaxis (PEP) and travel is potentially a significant barrier for exposed patients and their families, although safety nets are in place to provide the prophylaxis at no cost for low-income families. A decision-tree model was built to estimate changes in the costs from the patients' perspective and the survival outcomes of the Institut Pasteur du Cambodge (IPC) rabies PEP regimen after the switch from the Thai Red Cross (TRC) rabies PEP regimen in patients exposed to WHO category II or III bites by dogs. Derived from the IPC database, data included the trajectory of 203,497 patients, 1412 called-back patients and economic data on 201 patients. Uncertainty was addressed using one-way and probabilistic sensitivity analyses. Compared to the TRC regimen, the IPC regimen was cheaper and equally effective in patients with category II bites. In patients with category III bites, the IPC regimen was cheaper and its modeled probability of survival was 0.04% (95% CI, −0.12%; 0%) lower than the TRC regimen. However, the mortality rate was very low and the causes of death were uncertain. The data available may have lacked power to be able to statistically significantly tell apart the difference between genuine PEP failure and incorrect PEP administration, in the three versus the four-PEP sessions.