Meningococcal Disease Glossary of Terms

Bacterial meningitis: a serious infection of the membranes surrounding the brain and spinal cord, caused by certain bacteria, such as Neisseria meningitidis

Booster: another dose of an immunizing agent administered after a patient has received the primary vaccination series. The booster dose is intended to stimulate immunologic memory response to sustain the immune response produced by the primary dose or doses

Boostable memory response: an attribute of the immune system by which an encounter with an antigen induces a heightened state of immune reactivity and the additional production of antibodies

Carriage: the presence of bacteria in an individual that does not cause disease in that individual, but can spread to others and cause illness

Herd immunity: protection of unvaccinated individuals from a particular disease due to immunity that exists in the majority of the population, usually because of high vaccination rates

Hib vaccine: a vaccine that provides immunization against Haemophilus influenzae type b, a bacterium that can cause one type of meningitis, usually in infants and children younger than 2 years of age

Immunization: the process by which a person mounts an immune response after exposure to a foreign antigen; often used interchangeably with vaccination or inoculation

Inflammation: changes in the tissues of the body in response to infection, injury, or disease; signs of inflammation include swelling, pain, heat, and redness

Meninges: three-layer lining that protects and cushions the brain and spinal cord

Meningitis: inflammation of the meninges

Meningococcal disease: a bacterial infection that often causes severe swelling of the membranes surrounding the brain and spinal cord or a serious blood infection; caused by Neisseria meningitidis

Meningococcal meningitis: severe swelling of the membranes surrounding the brain and spinal cord (meninges) caused by Neisseria meningitidis

Meningococcal vaccine: any vaccine that provides protection against Neisseria meningitidis, a bacterium that can cause meningitis or severe bloodstream infection

Meningococcemia: infection of the blood (sepsis) caused by Neisseria meningitidis

Neisseria meningitidis: the bacterium that causes meningococcal disease

Outbreak: an increase in the number of cases of a specific infectious illness within a setting or population, over a specific timeframe. The number of cases needed to declare an outbreak varies by disease and the size of the setting or population.

Pneumococcal vaccine: a vaccine that provides protection against Streptococcus pneumoniae, a bacterium that can cause one type of meningitis

Purpuric rash: A potential sign of meningococcal disease; typically appears as flat, dark purple spots on the arms, legs and then the torso or trunk

Quadrivalent meningococcal vaccine: a vaccine that protects against infection from four meningococcal serogroups (A, C, W, and Y)

Secondary case: a case of disease that occurs among close contacts of a primary case-patient 24 hours after onset of illness in the primary case

Serogroup: a group of closely related organisms having similar antigens; types of bacteria that cause meningococcal disease (A, B, C, W, and Y)

Serogroup B meningococcal vaccine: a vaccine that protects against meningococcal serogroup B infection

Titer: the measure of the level of antibodies in blood

Vaccine: an antigenic formulation that produces immunity, protecting the body from disease

Viral meningitis: meningitis caused by a virus; usually less severe than bacterial meningitis and cannot be prevented through vaccination