Meningococcal disease

Meningococcal meningitis is a life-threatening infection of the fluid and tissues surrounding the brain, caused by a bacterium known as Neisseria meningitides. The infection is spread person-to-person by exposure to secretions from the nose or throat. In most countries, meningococcal meningitis occurs sporadically, with small outbreaks occurring in closed communities, such as dormitories or military barracks. However, certain countries in sub-Saharan Africa, known as the "meningitis belt," periodically experience major epidemics, especially in the dry season (December through June).

The incubation period ranges from two to ten days. Most people who are infected show no symptoms, but some develop meningitis, marked by the abrupt onset of fever, headache, stiff neck, and lethargy, frequently with a rash. Meningococcal meningitis must be promptly treated with intravenous antibiotics, usually penicillin, ampicillin, or ceftriaxone. The fatality rate may approach 10%, despite appropriate therapy. Among survivors, long-term complications may include deafness, seizures, or mental impairment.

Meningococcal meningitis is rare among travelers. Meningococcal vaccine is recommended chiefly for travel to countries in the African "meningitis belt" during the dry season (December through June), especially if prolonged contact with the local populace is likely. In addition, the vaccine is periodically recommended for other countries reporting meningitis outbreaks. Immunization is required for travel to Mecca during the Hajj.

Meningococcal vaccine consists of purified polysaccharides from the bacterial capsule, rather than live or killed bacteria. The main side-effect is mild redness at the injection site. Fever is uncommon. Serious reactions are not reported. Protective antibodies develop 10-14 days after vaccination.

There are two meningococcal vaccines currently licensed in the United States. A new quadrivalent conjugate vaccine called Menactra; Sanofi-Pasteur appears to provide longer-lasting protection than an older vaccine, called (Menomune - A/C/Y/W-135; Aventis Pasteur Inc.). Both vaccines confer protection against four groups of Neisseria meningitides (A, C, Y, and W-135) but not group B, which may also cause epidemics. If at continued risk, children previously vaccinated at ages 2 through 6 years should receive an additional dose of Menactra three years after their previous meningococcal vaccine and every five years thereafter. Persons previously vaccinated at ages 7 through 55 years should receive an additional dose of Menactra five years after their previous dose and every five years thereafter, if at continued risk.

In countries other than the United States, polysaccharide vaccines limited to groups A and C (bivalent) are also available. Since an increase in the number of meningococcal infections caused by group W-135 has recently been reported (see World Health Organization), bivalent vaccines should not in general be used for international travel. A protein-polysaccharide conjugate vaccine against group C meningococci has recently become available in Canada and the United Kingdom. Unlike the older polysaccharide vaccines, the conjugate vaccine is effective in infants and young children. However, since most outbreaks in developing nations are caused by meningococci belonging to groups other than C, this vaccine is generally not adequate for international travel.

Regardless of immunization status, anyone who potentially has had direct contact with the oral or nasal secretions of an infected person should be treated prophylactically with rifampin 600 mg twice daily for 48 hours, a single 500 mg dose of ciprofloxacin, or a single 250 mg intramuscular dose of ceftriaxone. Those treated should include household contacts and anyone who sat next to an infected person during an extended plane flight.

Menomune is available in 10-dose and single-dose vials. The manufacturer recently received FDA approval to extend the use of the 10-dose vial, after reconstitution, from 10 to 35 days.

From the World Health Organization (WHO)

Meningococcal vaccines: polysaccharide and polysaccharide conjugate vaccines (WHO position paper) (PDF)

Meningococcal meningitis fact sheet

Number of cases and deaths of meningococcal disease reported to WHO: 1998; 1999; 2000

Epidemics of meningococcal disease, African meningitis belt, 2001 (PDF)

Meningococcal vaccine

Safety of meningococcal vaccine

Group A and C meningococcal vaccines: WHO position paper (PDF)

From the Centers for Disease Control (CDC

Prevention and Control of Meningococcal Disease: Recommendations of the Advisory Committee on Immunization Practices (ACIP)

Exposure to Patients With Meningococcal Disease on Aircrafts ---United States, 1999--2001

From Immunization Action Coalition

Meningococcal information