Rabies antibody response after two intradermal pre-exposure prophylaxis immunizations: An observational cohort study.

BACKGROUND: Rabies is a lethal, but vaccine preventable disease. Vaccination uptake is however hampered by the time-consuming three-dose, 21/28-day schedule. The aim of this study was to examine whether adequate rabies antibody titers are reached after two intradermal (ID) doses of rabies vaccine, with a seven-day window.

METHOD: We conducted an observational cohort study with military personnel. A titer was assessed by RFFIT, on the day of the third vaccination, to ensure an adequate rabies antibody response after ID immunization.

RESULTS: After this abbreviated two-dose, seven-day ID schedule, seroconversion was reached in 99.3% (427/430) with a geometric mean titer of 7.59 IU/mL (95% CI 7.04-8.17).

CONCLUSIONS: Implementation of this two-dose schedule will protect more people against Rabies. Travelers and military personnel under time constraints, who otherwise would remain unvaccinated, can be considered adequately protected after this two-dose schedule. For populations in endemic areas, local application of a two-dose schedule could provide an opportunity to vaccinate more people with less vaccine. Given the paucity of published data, this study adds relevant evidence in support of the new policy (2017) of WHO, concerning a two-dose, seven-day schedule is approved for all healthy individuals.