Children's Vaccines Health Center

Meningococcal Vaccine

Meningococcal disease is an infection caused by a strain of bacteria called Neisseria meningitidis. This nasty bug is one of the leading causes of bacterial meningitis in children aged 2 to 18 in the U.S.

Meningococcal disease can include meningitis -- a serious, potentially life-threatening inflammation of the membranes covering the brain and spinal cord -- and a life-threatening blood infection. Meningococcal disease can cause limb loss through amputation, hearing loss, problems with the nervous system, mental retardation, seizures, and strokes.

Fortunately, meningococcal disease is preventable, and the key to prevention is the meningococcal vaccine. Here is information about the vaccine that you can use to help protect yourself and your family from meningococcal disease.

How Is Meningococcal Disease Spread and Who Is Most at Risk?

Meningococcal disease is not as contagious as other illnesses, such as a cold or the flu. But it is spread by contact with infected respiratory and throat secretions. That can happen with coughing, kissing, or sneezing.

Because the risk increases with close or prolonged contact with an infected person, family members in the same household and caregivers are at an increased risk. For the same reason, so are college students who live in dormitories.

Can the Meningococcal Vaccine Cause Meningococcal Disease?

The short answer is no. There are actually two meningococcal vaccines licensed in the U.S. Neither of the vaccines contains live bacteria.

The vaccines contain antigens -- substances that trigger the body's immune system and cause it to make antibodies. These antibodies then protect the body by attacking and killing the bacteria if it should invade.

The first vaccine -- meningococcal polysaccharide vaccine or MPSV4 -- was approved in 1978. It's made with the antigens contained in the outer polysaccharide or sugar capsule that surrounds the bacterium.

The newer vaccine, approved in 2005, is the meningococcal conjugate vaccine or MCV4. It uses antigens taken from the polysaccharide capsule and then bound to a separate protein that targets the body's immune cells. This makes it easier for the body's immune system to see and recognize the antigens.

One type of MCV4, Menveo, is licensed for use in people aged 2 to 55. Another version, Menactra, is approved for those 9 months to 55 years old. MPSV4 is the only vaccine licensed for use in people over 55 as well as people 2 to 55. Both vaccines protect against four types of meningococcal disease.

Are Both Meningococcal Vaccines Equally Effective?

Both MCV4 and MPSV4 are about 90% effective in preventing meningococcal disease. There are actually several types of N meningitidis -- the bacterium that causes meningococcal disease. Both vaccines protect against four of those types, including two types that are the most common in the U.S.

MCV4 has not been available long enough to compare the long-term effectiveness of the two vaccines. But most experts think that MCV4 provides better, longer-lasting protection.