Immunizations Back-Up Technician Practice Test 2026 - Free Practice Questions and Study Guide

Immunity from the anthrax vaccine wanes over time, so for anyone with ongoing exposure risk, a yearly booster is recommended to keep protective antibody levels high. After the initial vaccination series, antibody titers decline, and giving a booster each year rapidly raises those titers again and reinforces immune memory, helping ensure continued protection if exposure occurs. Longer intervals (every two, five, or ten years) allow protection to fall below the needed level in people who remain at risk, making annual boosters the best way to maintain effective immunity when continued protection is required.