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.
Meningococcal bacteria can be spread from person to person through saliva, most commonly through coughing or kissing. It can spread quickly when people are living in close quarters like college dorms. Vaccination is needed before exposure.