Meningococcal vaccine
Encyclopedia
Meningococcal vaccine is a vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...

 used against Meningococcus, a bacterium that causes meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...

, meningococcemia
Meningococcemia
Meningococcal disease describes infections caused by the bacterium Neisseria meningitidis . It carries a high mortality rate if untreated. While best known as a cause of meningitis, widespread blood infection is more damaging and dangerous...

, septicemia, and rarely carditis
Carditis
Carditis is the inflammation of the heart or its surroundings.It is usually studied and treated by specifying it as:*Pericarditis is the inflammation of the pericardium*Myocarditis is the inflammation of the heart muscle...

, septic arthritis
Septic arthritis
Septic arthritis is the purulent invasion of a joint by an infectious agent which produces arthritis. People with artificial joints are more at risk than the general population but have slightly different symptoms, are infected with different organisms and require different treatment. Septic...

, or pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...

.

Types

Neisseria meningitidis
Neisseria meningitidis
Neisseria meningitidis, often referred to as meningococcus, is a bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life threatening sepsis. N. meningitidis is a major cause of morbidity and mortality during childhood in industrialized countries...

has 13 clinically significant serogroups
Serotype
Serotype or serovar refers to distinct variations within a subspecies of bacteria or viruses. These microorganisms, viruses, or cells are classified together based on their cell surface antigens...

. These are classified according to the antigenic structure of their polysaccharide capsule. Six serogroups, A, B, C, Y, W135 and X are responsible for virtually all cases of the disease in humans.

Quadrivalent (Serogroups A, C, W-135 and Y)

There are currently three vaccines available in the US to prevent meningococcal disease, all quadrivalent in nature, targeting serogroups A, C, W-135 and Y:
  • two conjugate vaccine
    Conjugate vaccine
    A conjugate vaccine is created by covalently attaching a poor antigen to a carrier protein , thereby conferring the immunological attributes of the carrier on the attached antigen...

    s (MCV-4), Menactra and Menveo, and
  • one polysaccharide
    Polysaccharide
    Polysaccharides are long carbohydrate molecules, of repeated monomer units joined together by glycosidic bonds. They range in structure from linear to highly branched. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure,...

     vaccine (MPSV-4), Menomune, produced by Sanofi Pasteur
    Sanofi pasteur
    Sanofi Pasteur is the vaccines division of sanofi-aventis Group. It is the largest company in the world devoted entirely to vaccines.- History :...

    .


Mencevax (GlaxoSmithKline
GlaxoSmithKline
GlaxoSmithKline plc is a global pharmaceutical, biologics, vaccines and consumer healthcare company headquartered in London, United Kingdom...

) and NmVac4-A/C/Y/W-135
NmVac4-A/C/Y/W-135
NmVac4-A/C/Y/W-135 is the commercial name of the Meningococcal meningitis polysaccharide serogroups A,C,Y and W-135 vaccine of JN-International Medical Corporation...

 (JN-International Medical Corporation
JN-International Medical Corporation
JN-International Medical Corporation is a U.S. based biopharmaceutical corporation which since 1998 has been focused on developing vaccines and diagnostics for infectious disease for developing countries. This private corporation was founded in 1998 by Dr. Jeeri R. Reddy with the help of Dr. Kelly F...

) are used worldwide, but have not been licensed in the United States.

The first meningococcal conjugate vaccine (MCV4), Menactra, was licensed in the U.S. in 2005 by Sanofi Pasteur
Sanofi pasteur
Sanofi Pasteur is the vaccines division of sanofi-aventis Group. It is the largest company in the world devoted entirely to vaccines.- History :...

; Menveo, was licensed in 2010 by Novartis
Novartis
Novartis International AG is a multinational pharmaceutical company based in Basel, Switzerland, ranking number three in sales among the world-wide industry...

. Both MCV4 vaccines have been approved by the Food and Drug Administration
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...

 (FDA) for people 2 through 55 years of age. In April 2011, Menactra received FDA approval for use in children as young as 9 months, although the Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...

 (CDC) has not made recommendations for or against its use in children less than 2.

Meningococcal polysaccharide vaccine (MPSV4), Menomune, has been available since the 1970s. It may be used if MCV4 is not available, and is the only meningococcal vaccine licensed for people older than 55. Information about who should receive the meningococcal vaccine is available from the CDC.

Limitations

The duration of immunity mediated by Menomune (MPSV4) is three years or less in children aged under 5 because it does not generate memory T cells. Attempting to overcome this problem by repeated immunization results in a diminished not increased antibody
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

 response, so boosters are not recommended with this vaccine. As with all polysaccharide vaccines, Menomune does not produce mucosal immunity, so people can still become colonised with virulent strains of meningococcus, and no herd immunity
Herd immunity
Herd immunity describes a form of immunity that occurs when the vaccination of a significant portion of a population provides a measure of protection for individuals who have not developed immunity...

 can develop. For this reason, Menomune is suitable for travelers requiring short-term protection, but not for national public health prevention programs.

Menveo and Menactra contain the same antigens as Menomune, but the antigens are conjugated to a diphtheria-toxoid
Diphtheria toxin
Diphtheria toxin is an exotoxin secreted by Corynebacterium diphtheriae, the pathogen bacterium that causes diphtheria. Unusually, the toxin gene is encoded by a bacteriophage...

 polysaccharide–protein complex, resulting in anticipated enhanced duration of protection, increased immunity with booster vaccinations, and effective herd immunity.

Endurance

A study published in March 2006 comparing the two kinds of vaccines found that 76% of subjects still had passive protection three years after receiving MCV-4 (63% protective compared with controls), but only 49% has passive protection after receiving MSPV-4 (31% protective compared with controls). As of 2010, there remains limited evidence that any of the current conjugate vaccines offer continued protection beyond three years; studies are ongoing to determine the actual duration of immunity, and the subsequent requirement of booster vaccinations. The CDC offers recommendations regarding who they feel should get booster vaccinations.

Serogroup A

A vaccine called MenAfriVac
MenAfriVac
MenAfriVac is a vaccine developed for use in sub-Saharan Africa that protects people 1 to 29 years of age against meningococcal bacterium Neisseria meningitidis group A. MenAfriVac costs under US$.50 per dose and reduces carriage of the bacteria from one person to another...

 has been developed through a program called the Meningitis Vaccine Project
Meningitis Vaccine Project
The Meningitis Vaccine Project is an effort to eliminate the meningitis epidemic in Sub-Saharan Africa by developing a new meningococcal vaccine. The meningitis problem in that area is caused by a strain of meningitis called "meningitis A", which is only present in the African meningitis belt...

 and it is a good option for preventing meningitis group A infections.

Serogroup B

A vaccine for serogroup B was developed in Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...

 in response to a large outbreak of meningitis B during the 1980s. The VA-MENGOC-BC vaccine proved safe and effective in randomized double-blind studies, but it was granted a license only for research purposes in the United States as political differences limited cooperation between the two countries.

Due to a similarly high prevalence of B-serotype meningitis in Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

 between 1975 and 1985, Norwegian health authorities developed a vaccine specifically designed for Norwegian children and young adolescents. Clinical trials were discontinued after the vaccine was shown to cover only slightly more than 50% of all cases. Furthermore, lawsuits for damages were filed against the State of Norway by persons affected by serious adverse reactions. Information that the health authorities obtained during the vaccine development were subsequently passed on to Chiron
Chiron
In Greek mythology, Chiron was held to be the superlative centaur among his brethren.-History:Like the satyrs, centaurs were notorious for being wild and lusty, overly indulgent drinkers and carousers, given to violence when intoxicated, and generally uncultured delinquents...

 (now a Novartis subsidiary), who developed a similar vaccine, MeNZB
MeNZB
MeNZB was a vaccine against a specific strain of group B meningococcus, used to control an epidemic of meningococcal disease in New Zealand. Most people are able to carry the meningococcus bacteria safely with no ill effects...

, for New Zealand.

Serogroup X

The occurrence of serogroup X was reported in North America, Europe, Australia, and West Africa. Current meningoccocal meningitis vaccine is not known to protect from serogroup X N. meningitidis disease.
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