The anti-rabies vaccine in humans is generally effective for several years, often up to 10 years or more, especially when booster doses are given. After the initial post-exposure prophylaxis (PEP) course of 4-5 doses over 2-4 weeks, people are considered protected from immediate rabies risk. For pre- exposure prophylaxis (PrEP), the initial 2-3 doses provide immunity that may last years, but boosters are recommended every few years, especially for those at high risk. Studies show antibody levels can persist up to 5 years or more, and boosters given at this point can restore strong immunity. Typically, healthy individuals develop long-lasting immunity with occasional boosters, while high-risk individuals may need boosters every 1 to 2 years to ensure continued protection.

Key Points:

• Post-exposure vaccine series (4-5 doses) provide nearly 100% protection in the short term.
• Immunity after vaccination often lasts for many years (up to 10 years or longer with boosters).
• Boosters are recommended for high-risk individuals every 6 months to 2 years.
• Immune protection without boosters may diminish over 5 years but can be restored with a booster.
• For most people, a booster after several years maintains long-term immunity.

This means the anti-rabies vaccine effectiveness duration varies with context but can last many years with appropriate boosters.