Neisseria meningitidis
Encyclopedia
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 and has been responsible for epidemics in Africa and in Asia. Upon Gram staining
, it appears as a Gram-negative
diplococcus
and cultures of the bacteria test positive for the enzyme oxidase
.
Approximately 2500 to 3500 cases of N. meningitidis infection occur annually in the United States, with a case rate of about 1 in 100,000. Children younger than 5 years are at greatest risk, followed by teenagers of high school age. Rates in sub-Saharan Africa can be as high as 1 in 1000 to 1 in 100.
Anton Weichselbaum
in 1887 first discovered the disease in patients infected with meningococci.
Meningococci only infect humans and have never been isolated from animals because the bacterium cannot get iron other than from human sources (transferrin
and lactoferrin
).
It exists as normal flora (nonpathogenic) in the nasopharynx
of up to 5-15% of adults. It causes the only form of bacterial meningitis
known to occur epidemic
ally. Streptococcus pneumoniae
(aka) pneumococcus is the most common bacterial etiology of meningitis in children beyond 2 months of age(1-3 per 100,000).
Meningococcus is spread through the exchange of saliva and other respiratory secretions during activities like coughing, kissing, and chewing on toys. Though it initially produces general symptoms like fatigue, it can rapidly progress from fever, headache and neck stiffness to coma
and death. The symptoms are easily confused with those of meningitis caused by other organisms such as Hemophilus influenzae and Streptococcus pneumoniae
. Death occurs in approximately 10% of cases. Those with impaired immunity may be at particular risk of meningococcus (e.g. those with nephrotic syndrome
or splenectomy
; vaccines are given in cases of removed or non-functioning spleens
).
Suspicion of meningitis is a medical emergency
and immediate medical assessment is recommended. Current guidance in the United Kingdom is that if a case of meningococcal meningitis or septicaemia
(infection of the blood) is suspected intravenous antibiotics should be given and the ill person admitted to the hospital. This means that laboratory tests may be less likely to confirm the presence of Neisseria meningitidis as the antibiotics will dramatically lower the number of bacteria in the body. The UK guidance is based on the idea that the reduced ability to identify the bacteria is outweighed by reduced chance of death
.
Septicaemia caused by Neisseria meningitidis has received much less public attention than meningococcal meningitis even though septicaemia has been linked to infant deaths. Meningococcal septicaemia typically causes a purpuric rash that does not lose its color when pressed with a glass ("non-blanching") and does not cause the classical symptoms of meningitis. This means the condition may be ignored by those not aware of the significance of the rash. Septicaemia carries an approximate 50% mortality rate
over a few hours from initial onset. Many health organizations advise anyone with a non-blanching rash to go to a hospital as soon as possible. Note that not all cases of a purpura
-like rash are due to meningococcal septicaemia; however, other possible causes need prompt investigation as well (e.g. ITP
a platelet
disorder or Henoch-Schönlein purpura
).
Other severe complications include Waterhouse-Friderichsen syndrome
(a massive, usually bilateral, hemorrhage into the adrenal glands caused by fulminant meningococcemia), adrenal insufficiency, and disseminated intravascular coagulation
.
structure of their polysaccharide
capsule. Of the twelve groups of N. meningitidis have been identified, five of these (A, B, C, W135, and X) are able to cause epidemics.
of N. meningitidis which acts as an endotoxin
which is responsible for fever, septic shock
, and hemorrhage due to the destruction of red blood cells. Other virulence factors include a polysaccharide capsule which prevents host phagocytosis and aids in evasion of the host immune response; and fimbriae which mediate attachment of the bacterium to the epithelial cells of the nasopharynx
.
Recently a hypervirulent strain was discovered in China. Its impact is yet to be determined.
. Like most bacterial intracellular pathogens, N. meningitidis exploits host cell signaling pathways to promote its uptake by host cells. N.meningitidis does not have a type III secretion system nor a type IV secretion system. The signaling leading to bacterial internalization is induced by the type IV pili, which are the main means of meningococcal adhesion onto host cells. The signaling induced following Type IV pilus-mediated adhesion is responsible for the formation of microvilli-like structures at the site of the bacterial-cell interaction. These microvilli trigger the internalization of the bacteria into host cells. A major consequence of these signaling events is a reorganization of the actin
cytoskeleton
, which leads to the formation of membrane protrusions, engulfing bacterial pathogens into intracellular vacuole
s. Efficient internalization of N. meningitidis also requires the activation of an alternative signaling pathway coupled with the activation of the tyrosine kinase
receptor ErbB2. Beside Type IV pili, other outer membrane proteins may be involved in other mechanism of bacteria internalization into cells.
specimen is sent to the laboratory immediately for identification of the organism. Diagnosis relies on culturing the organism on a chocolate agar
plate. Further testing to differentiate the species includes testing for oxidase
, catalase
(all clinically relevant Neisseria show a positive reaction) and the carbohydrates maltose
, sucrose
, and glucose
test in which N. meningitidis will ferment (that is, utilize) the glucose and maltose. Serology
determines the subgroup
of the organism.
If the bacteria reach the circulation, then blood cultures should be drawn and processed accordingly.
Clinical tests that are used currently for the diagnosis of meningococcal disease take between 2 and 48 hours and often rely on the culturing of bacteria from either blood or cerebrospinal fluid (CSF) samples. However, polymerase chain reaction
tests can be used to identify the organism even after antibiotics have begun to reduce the infection. As the disease has a fatality risk approaching 15% within 12 hours of infection, it is crucial to initiate testing as quickly as possible but not to wait for the results before initiating antibiotic therapy.
(CSF) for laboratory testing, cannot be done within 30 minutes of admission to hospital. Antibiotic treatment may affect the results of microbiology tests, but a diagnosis may be made on the basis of blood-cultures and clinical examination.
.
There are currently three vaccines available in the U.S. to prevent meningococcal disease. All three vaccines are effective against the same serogroups: A, C, Y, and W-135. Two meningococcal conjugate vaccines (MCV4) are licensed for use in the U.S. The first conjugate vaccine was licensed in 2005, the second in 2010. Conjugate vaccines are the preferred vaccine for people 2 through 55 years of age. A meningococcal polysaccharide vaccine (MPSV4) has been available since the 1970s and is the only meningococcal vaccine licensed for people older than 55. MPSV4 may be used in people ages 2 - 55 years old if the MCV4 vaccines are not available or contraindicated. Information about who should receive the meningococcal vaccine is available from the Centers for Disease Control and Prevention (CDC)
.
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...
and other forms of meningococcal disease such as meningococcemia, a life threatening sepsis
Sepsis
Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...
. N. meningitidis is a major cause of morbidity and mortality during childhood in industrialized countries and has been responsible for epidemics in Africa and in Asia. Upon Gram staining
Gram staining
Gram staining is a method of differentiating bacterial species into two large groups ....
, it appears as a Gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
diplococcus
Diplococcus
A diplococcus is a round bacterium that typically occurs in the form of two joined cells. Examples are Streptococcus pneumoniae, Moraxella catarrhalis, Neisseria gonorrhoeae and Neisseria meningitidis...
and cultures of the bacteria test positive for the enzyme oxidase
Oxidase
An oxidase is any enzyme that catalyzes an oxidation-reduction reaction involving molecular oxygen as the electron acceptor. In these reactions, oxygen is reduced to water or hydrogen peroxide ....
.
Approximately 2500 to 3500 cases of N. meningitidis infection occur annually in the United States, with a case rate of about 1 in 100,000. Children younger than 5 years are at greatest risk, followed by teenagers of high school age. Rates in sub-Saharan Africa can be as high as 1 in 1000 to 1 in 100.
Anton Weichselbaum
Anton Weichselbaum
Anton Weichselbaum was an Austrian pathologist and bacteriologist who was a native of Schiltern....
in 1887 first discovered the disease in patients infected with meningococci.
Meningococci only infect humans and have never been isolated from animals because the bacterium cannot get iron other than from human sources (transferrin
Transferrin
Transferrins are iron-binding blood plasma glycoproteins that control the level of free iron in biological fluids. In humans, it is encoded by the TF gene.Transferrin is a glycoprotein that binds iron very tightly but reversibly...
and lactoferrin
Lactoferrin
Lactoferrin , also known as lactotransferrin , is a multifunctional protein of the transferrin family. Lactoferrin is a globular glycoprotein with a molecular mass of about 80 kDa that is widely represented in various secretory fluids, such as milk, saliva, tears, and nasal secretions...
).
It exists as normal flora (nonpathogenic) in the nasopharynx
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...
of up to 5-15% of adults. It causes the only form of bacterial 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...
known to occur epidemic
Epidemic
In epidemiology, an epidemic , occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience...
ally. Streptococcus pneumoniae
Streptococcus pneumoniae
Streptococcus pneumoniae, or pneumococcus, is Gram-positive, alpha-hemolytic, aerotolerant anaerobic member of the genus Streptococcus. A significant human pathogenic bacterium, S...
(aka) pneumococcus is the most common bacterial etiology of meningitis in children beyond 2 months of age(1-3 per 100,000).
Meningococcus is spread through the exchange of saliva and other respiratory secretions during activities like coughing, kissing, and chewing on toys. Though it initially produces general symptoms like fatigue, it can rapidly progress from fever, headache and neck stiffness to coma
Coma
In medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
and death. The symptoms are easily confused with those of meningitis caused by other organisms such as Hemophilus influenzae and Streptococcus pneumoniae
Streptococcus pneumoniae
Streptococcus pneumoniae, or pneumococcus, is Gram-positive, alpha-hemolytic, aerotolerant anaerobic member of the genus Streptococcus. A significant human pathogenic bacterium, S...
. Death occurs in approximately 10% of cases. Those with impaired immunity may be at particular risk of meningococcus (e.g. those with nephrotic syndrome
Nephrotic syndrome
Nephrotic syndrome is a nonspecific disorder in which the kidneys are damaged, causing them to leak large amounts of protein from the blood into the urine....
or splenectomy
Splenectomy
A splenectomy is a surgical procedure that partially or completely removes the spleen.-Indications:The spleen, similar in structure to a large lymph node, acts as a blood filter. Current knowledge of its purpose includes the removal of old red blood cells and platelets, and the detection and fight...
; vaccines are given in cases of removed or non-functioning spleens
Asplenia
Asplenia refers to the absence of normal spleen function and is associated with some serious infection risks. Hyposplenism is used to describe reduced splenic functioning, but not as severely affected as with asplenism.-Congenital:...
).
Suspicion of meningitis is a medical emergency
Medical emergency
A medical emergency is an injury or illness that is acute and poses an immediate risk to a person's life or long term health. These emergencies may require assistance from another person, who should ideally be suitably qualified to do so, although some of these emergencies can be dealt with by the...
and immediate medical assessment is recommended. Current guidance in the United Kingdom is that if a case of meningococcal meningitis or septicaemia
Sepsis
Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...
(infection of the blood) is suspected intravenous antibiotics should be given and the ill person admitted to the hospital. This means that laboratory tests may be less likely to confirm the presence of Neisseria meningitidis as the antibiotics will dramatically lower the number of bacteria in the body. The UK guidance is based on the idea that the reduced ability to identify the bacteria is outweighed by reduced chance of death
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...
.
Septicaemia caused by Neisseria meningitidis has received much less public attention than meningococcal meningitis even though septicaemia has been linked to infant deaths. Meningococcal septicaemia typically causes a purpuric rash that does not lose its color when pressed with a glass ("non-blanching") and does not cause the classical symptoms of meningitis. This means the condition may be ignored by those not aware of the significance of the rash. Septicaemia carries an approximate 50% mortality rate
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...
over a few hours from initial onset. Many health organizations advise anyone with a non-blanching rash to go to a hospital as soon as possible. Note that not all cases of a purpura
Purpura
Purpura is the appearance of red or purple discolorations on the skin that do not blanch on applying pressure. They are caused by bleeding underneath the skin...
-like rash are due to meningococcal septicaemia; however, other possible causes need prompt investigation as well (e.g. ITP
Idiopathic thrombocytopenic purpura
Idiopathic thrombocytopenic purpura is the condition of having an abnormally low platelet count of no known cause . As most incidents of ITP appear to be related to the production of antibodies against platelets, immune thrombocytopenic purpura or immune thrombocytopenia are terms also used to...
a platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days...
disorder or Henoch-Schönlein purpura
Henoch-Schönlein purpura
Henoch–Schönlein purpura is a disease of the skin and other organs that most commonly affects children. In the skin, the disease causes palpable purpura ; often with joint and abdominal pain...
).
Other severe complications include Waterhouse-Friderichsen syndrome
Waterhouse-Friderichsen syndrome
Waterhouse-Friderichsen syndrome or hemorrhagic adrenalitis or Fulminant meningococcemia, is a disease of the adrenal glands most commonly caused by the bacterium Neisseria meningitidis. The infection leads to massive hemorrhage into one or both adrenal glands...
(a massive, usually bilateral, hemorrhage into the adrenal glands caused by fulminant meningococcemia), adrenal insufficiency, and disseminated intravascular coagulation
Disseminated intravascular coagulation
Disseminated intravascular coagulation , also known as disseminated intravascular coagulopathy or consumptive coagulopathy, is a pathological activation of coagulation mechanisms that happens in response to a variety of diseases. DIC leads to the formation of small blood clots inside the blood...
.
Subtypes
These are classified according to the antigenicAntigen
An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...
structure of their 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,...
capsule. Of the twelve groups of N. meningitidis have been identified, five of these (A, B, C, W135, and X) are able to cause epidemics.
Virulence
Lipooligosaccharide (LOS) is a component of the outer membraneOuter membrane
The bacterial outer membrane is found in Gram-negative bacteria. Its composition is distinct from that of the cytoplasmic membrane - among other things, the outer leaflet of the membrane includes a complex lipopolysaccharide whose lipid portion acts as an endotoxin - and it is linked to the cell's...
of N. meningitidis which acts as an endotoxin
Endotoxin
Endotoxins are toxins associated with some Gram-negative bacteria. An "endotoxin" is a toxin that is a structural molecule of the bacteria that is recognized by the immune system.-Gram negative:...
which is responsible for fever, septic shock
Septic shock
Septic shock is a medical emergency caused by decreased tissue perfusion and oxygen delivery as a result of severe infection and sepsis, though the microbe may be systemic or localized to a particular site. It can cause multiple organ dysfunction syndrome and death...
, and hemorrhage due to the destruction of red blood cells. Other virulence factors include a polysaccharide capsule which prevents host phagocytosis and aids in evasion of the host immune response; and fimbriae which mediate attachment of the bacterium to the epithelial cells of the nasopharynx
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...
.
Recently a hypervirulent strain was discovered in China. Its impact is yet to be determined.
Mechanisms of cellular invasion
N. meningitidis is an intracellular human-specific pathogen responsible for septicemia and meningitisMeningitis
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...
. Like most bacterial intracellular pathogens, N. meningitidis exploits host cell signaling pathways to promote its uptake by host cells. N.meningitidis does not have a type III secretion system nor a type IV secretion system. The signaling leading to bacterial internalization is induced by the type IV pili, which are the main means of meningococcal adhesion onto host cells. The signaling induced following Type IV pilus-mediated adhesion is responsible for the formation of microvilli-like structures at the site of the bacterial-cell interaction. These microvilli trigger the internalization of the bacteria into host cells. A major consequence of these signaling events is a reorganization of the actin
Actin
Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...
cytoskeleton
Cytoskeleton
The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein. The cytoskeleton is present in all cells; it was once thought to be unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton...
, which leads to the formation of membrane protrusions, engulfing bacterial pathogens into intracellular vacuole
Vacuole
A vacuole is a membrane-bound organelle which is present in all plant and fungal cells and some protist, animal and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain...
s. Efficient internalization of N. meningitidis also requires the activation of an alternative signaling pathway coupled with the activation of the tyrosine kinase
Tyrosine kinase
A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to a protein in a cell. It functions as an "on" or "off" switch in many cellular functions....
receptor ErbB2. Beside Type IV pili, other outer membrane proteins may be involved in other mechanism of bacteria internalization into cells.
Diagnosis
The gold standard of diagnosis is isolation of N. meningitidis from sterile body fluid. A CSFCerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
specimen is sent to the laboratory immediately for identification of the organism. Diagnosis relies on culturing the organism on a chocolate agar
Chocolate agar
Chocolate agar - is a non-selective, enriched growth medium. It is a variant of the blood agar plate. It contains red blood cells, which have been lysed by heating very slowly to 56 °C. Chocolate agar is used for growing fastidious respiratory bacteria, such as Haemophilus influenzae...
plate. Further testing to differentiate the species includes testing for oxidase
Oxidase
An oxidase is any enzyme that catalyzes an oxidation-reduction reaction involving molecular oxygen as the electron acceptor. In these reactions, oxygen is reduced to water or hydrogen peroxide ....
, catalase
Catalase
Catalase is a common enzyme found in nearly all living organisms that are exposed to oxygen, where it catalyzes the decomposition of hydrogen peroxide to water and oxygen...
(all clinically relevant Neisseria show a positive reaction) and the carbohydrates maltose
Maltose
Maltose , or malt sugar, is a disaccharide formed from two units of glucose joined with an αbond, formed from a condensation reaction. The isomer "isomaltose" has two glucose molecules linked through an α bond. Maltose is the second member of an important biochemical series of glucose chains....
, sucrose
Sucrose
Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...
, and glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
test in which N. meningitidis will ferment (that is, utilize) the glucose and maltose. Serology
Serology
Serology is the scientific study of blood serum and other bodily fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum...
determines the subgroup
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...
of the organism.
If the bacteria reach the circulation, then blood cultures should be drawn and processed accordingly.
Clinical tests that are used currently for the diagnosis of meningococcal disease take between 2 and 48 hours and often rely on the culturing of bacteria from either blood or cerebrospinal fluid (CSF) samples. However, polymerase chain reaction
Polymerase chain reaction
The polymerase chain reaction is a scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence....
tests can be used to identify the organism even after antibiotics have begun to reduce the infection. As the disease has a fatality risk approaching 15% within 12 hours of infection, it is crucial to initiate testing as quickly as possible but not to wait for the results before initiating antibiotic therapy.
Treatment
Persons with confirmed N. meningitidis infection should be hospitalized immediately for treatment with antibiotics. Third-generation cephalosporin antibiotics (i.e. cefotaxime, ceftriaxone) should be used to treat a suspected or culture-proven meningococcal infection before antibiotic susceptibility results are available. Empirical treatment should also be considered if a lumbar puncture, to collect cerebrospinal fluidCerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
(CSF) for laboratory testing, cannot be done within 30 minutes of admission to hospital. Antibiotic treatment may affect the results of microbiology tests, but a diagnosis may be made on the basis of blood-cultures and clinical examination.
Prevention
All recent contacts of the infected patient over the 7 days before onset should receive medication to prevent them from contracting the infection. This especially includes young children and their child caregivers or nursery-school contacts, as well as anyone who had direct exposure to the patient through kissing, sharing utensils, or medical interventions such as mouth-to-mouth resuscitation. Anyone who frequently ate, slept or stayed at the patient's home during the 7 days before the onset of symptom, or those who sat beside the patient on an airplane flight of 8 hours or longer, should also receive chemoprophylaxisChemoprophylaxis
Chemoprophylaxis refers to the administration of a medication for the purpose of preventing disease or infection. Antibiotics, for example, may be administered to patients with disorders of immune system function to prevent bacterial infections...
.
There are currently three vaccines available in the U.S. to prevent meningococcal disease. All three vaccines are effective against the same serogroups: A, C, Y, and W-135. Two meningococcal conjugate vaccines (MCV4) are licensed for use in the U.S. The first conjugate vaccine was licensed in 2005, the second in 2010. Conjugate vaccines are the preferred vaccine for people 2 through 55 years of age. A meningococcal polysaccharide vaccine (MPSV4) has been available since the 1970s and is the only meningococcal vaccine licensed for people older than 55. MPSV4 may be used in people ages 2 - 55 years old if the MCV4 vaccines are not available or contraindicated. Information about who should receive the meningococcal vaccine is available from the Centers for Disease Control and Prevention (CDC)
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...
.