From the Guidelines
Three doses of meningococcal vaccine provide better protection than two doses for children, particularly in high-risk groups or during outbreaks, as evidenced by the most recent and highest quality study 1. The standard recommendation is a primary series of two doses of MenACWY vaccine given at ages 11-12 years with a booster dose at age 16, or two doses of MenB vaccine for adolescents and young adults. For high-risk infants and children, the dosing schedule is more intensive, with up to four doses of MenACWY starting as early as 2 months of age. Studies show that antibody levels decline significantly within 3-5 years after vaccination, which is why the booster dose is crucial for maintaining protection during the highest risk period in late adolescence. Some key points to consider include:
- The third dose (booster) increases antibody levels substantially and extends protection through the high-risk college years 1.
- Without this booster, immunity may wane precisely when exposure risk increases.
- Meningococcal disease, though rare, can be devastating with a 10-15% mortality rate and significant long-term complications in survivors, making complete vaccination essential for optimal protection.
- The ACIP recommends the use of either MenB vaccine for people 10 years and older at increased risk for meningococcal serogroup B disease, including people with persistent complement component deficiencies, people with anatomic or functional asplenia, people receiving eculizumab, microbiologists who work with Neisseria meningitidis, and people in outbreak settings 1. The benefits of the booster dose and a desire to continue to protect younger adolescents prompted the recommendation for a routine booster dose at age 16 years 1. In 2010, ACIP revised the recommendations for dosing regimens for persons who have functional or anatomic asplenia, who have persistent complement component deficiencies, or who have HIV infection and are otherwise recommended to be vaccinated 1. For these immunosuppressed persons, a 2-dose primary series was recommended instead of a single dose. For persons with persistent complement component deficiency, a 2-dose primary series will help achieve the high levels of SBA needed to confer protection in the absence of effective opsonization. Booster doses after primary vaccination are important for persons with prolonged increased risk to ensure high levels of SBA are maintained over time 1.
From the Research
Efficacy of 2 Doses vs 3 Doses of Meningitis Vaccine in Children
- The efficacy of 2 doses vs 3 doses of meningitis vaccine in children is a topic of ongoing research and debate 2, 3, 4, 5, 6.
- A study published in 2025 found that a two-dose pentavalent vaccine, with doses administered 6 months apart at 16 years of age, alongside the routinely recommended MenACWY vaccine at 11 years of age, would improve the public health impact and benefits of IMD vaccination to society 2.
- Another study published in 2019 found that a booster dose of quadrivalent meningococcal diphtheria toxoid conjugate vaccine (MenACWY-D) at age 16 years resulted in high proportions of participants maintaining protective antibody levels against IMD 3.
- A phase III study published in 2014 found that a two-dose or three-dose primary infant series of MenACWY-CRM, a quadrivalent meningococcal conjugate vaccine, elicited immune responses against the four serogroups in 94-100% of subjects, with noninferiority of the two- versus three-dose regimen established for geometric mean titers for all serogroups 4.
- The Advisory Committee on Immunization Practices (ACIP) has recommended the use of MenACWY-CRM vaccine in children aged 2 through 23 months at increased risk for meningococcal disease, with a two-dose or three-dose primary series depending on the age and risk factors of the child 5, 6.
- The ACIP has also recommended that all adolescents receive a booster dose of quadrivalent meningococcal conjugate vaccine at age 16 years, with the option to use either MenACWY-CRM or MenACWY-D vaccine 6.