Evidence of waning immunity by 5 years post-vaccination has led the US Advisory Committee on Immunization Practices (ACIP) to recommend, in addition to a primary dose of meningococcal conjugate vaccine at 11 or 12 years of age, a booster dose at age 16. Adolescents who receive a first dose of the vaccine at age 13-15 should receive a booster dose at 16-18 (before college). Those who receive their first dose at ≥16 years of age do not need a booster dose. Routine vaccination of healthy persons who are not at increased risk for exposure to Neisseria meningitidis is not recommended after age 21.1