Immune response to rabies post-exposure prophylaxis in patients with non-HIV secondary immunodeficiencies.

BACKGROUND: This study sought to determine the proportion of individuals with non-HIV secondary immunodeficiencies presenting inadequate antibody titers after rabies post-exposure prophylaxis (PEP) and to identify variables associated with inadequate response. METHODS: A retrospective review of the records of immunocompromised patients having received a full course of PEP after a rabies exposure and having been tested for post-PPE antibody titers in two French Antirabies Clinics, between 2013 and 2018, was conducted. Antibody titers < 0.5 EU/ml (ELISA) were classified as inadequate. RESULTS: A total of 28 individuals were included, 6 had inadequate post-PPE titers. None of the tested variable was independently associated with inadequate titers. CONCLUSIONS: Inadequate response was unpredictable and not explained either by the characteristics of patients or by the PEP regimen they received. These findings support the WHO recommendation to systematically assess post-PEP response in immunocompromised patients to detect non-responders, who might require an additional dose.