All 11 to 12 year olds should be vaccinated with a single dose of a meningococcal ACWY vaccine. Older teens need a second shot when they are 16 years old so they stay protected when their risk is the highest. Meningococcal B is given to anyone 16 through 23 years old to provide short term protection against most strains of serogroup B meningococcal disease; 16 through 18 years are the preferred ages for vaccination.