Effect of Antimalarial Drugs on the Immune Response to Intramuscular Rabies Vaccination Using a Postexposure...

Area of Science:

• Immunology
• Vaccinology
• Tropical Medicine

Background:

• Antimalarial drugs can affect immune responses to vaccines.
• Current guidelines suggest additional rabies vaccine doses for those on antimalarials.

Purpose of the Study:

• To evaluate the impact of chloroquine, Malarone, and doxycycline on antibody response to rabies vaccination.
• To compare immune responses across different antimalarial treatment groups.

Main Methods:

• A randomized, open-label study involved 103 unvaccinated adults.
• Participants received antimalarials before and during rabies vaccination.
• Antibody titers were measured post-vaccination.

Main Results:

• All subjects achieved protective rabies antibody titers (≥0.5 IU/mL).
• Chloroquine showed a reduction in rabies antibody geometric mean titer compared to controls (2.3 vs 6.87 IU/mL).
• Malarone and doxycycline did not significantly alter rabies antibody titers.

Conclusions:

• Malarone and doxycycline do not reduce rabies antibody response.
• Chloroquine significantly reduces rabies antibody response, though protective levels are still achieved.
• Accepted rabies antibody levels were achieved with all tested antimalarials.