If not treated with antibiotics, often within hours of the onset of symptoms, the disease can progress rapidly and can lead to shock and death. Appropriate antibiotic treatment of the common types of bacterial meningitis reduce the risk of death to below 15 percent. Those at Risk Meningococcal disease can affect people at any age. Certain groups are at increased risk of contracting the disease including those in close contact with a known case, persons with upper respiratory infections, and those with underlying illness or with compromised immune systems. On college campuses, freshmen living in dormitories have been found to have a modestly increased risk.
Persons traveling to endemic areas of the world are also at increased risk.
Other factors found to be associated with increased risk of meningococcal disease include active and passive smoking, a new residence, a new school, medicaid insurance, and household crowding. During outbreaks, bar or nightclub patronage and alcohol use also have been associated with higher risk of meningococcal disease. The vaccine is 85-100 percent effective in preventing serogroup A and C in older children and adults. It does not protect against serotype B, which accounts for 32 percent of cases in the 15-24 year old group. For this reason, in the event of an outbreak, even those individuals who have been previously immunized against meningococcal disease should contact their health care provider as the outbreak may be of a serotype not covered by the vaccine.