Chapter 3 Infectious Diseases Related To Travel
Amanda Cohn, Jessica R. MacNeil
Neisseria meningitidis is a gram-negative diplococcus. Meningococci are classified into serogroups on the basis of the composition of the capsular polysaccharide. The 5 major meningococcal serogroups associated with disease are A, B, C, Y, and W-135.
Person-to-person transmission occurs by close contact with respiratory secretions or saliva.
N. meningitidis is found worldwide. At any time, 5%–10% of the population may be carriers of N. meningitidis. Invasive disease is rare in nonepidemic areas, occurring at a rate of 0.5–10 cases per 100,000 population per year, but can occur at a rate of up to 1,000 cases per 100,000 population per year in epidemic regions.
The incidence of meningococcal disease is highest in the “meningitis belt” of sub-Saharan Africa (Map 3-11). The incidence of meningococcal disease is several times higher in the meningitis belt than in the United States, with periodic epidemics during the dry season (December–June). During nonepidemic periods, the rate of meningococcal disease in this region is roughly 5–10 cases per 100,000 population per year. During epidemics, the rate can be as high as 1,000 cases per 100,000 population. Although most common in the African meningitis belt, meningococcal outbreaks can occur anywhere in the world. Serogroup A predominates in the meningitis belt, although serogroups C, X, and W-135 are also found.
Young children have the highest risk for meningococcal disease, but 60% of cases occur in adolescents and adults. Risk is highest in travelers to the meningitis belt who have prolonged contact with local populations during an epidemic. The Hajj pilgrimage to Saudi Arabia has been associated with outbreaks of meningococcal disease in returning pilgrims and their contacts.
Meningococcal disease generally occurs 1–14 days after exposure and presents as meningitis in ≥50% of cases. Meningococcal meningitis is characterized by sudden onset of headache, fever, and stiffness of the neck, sometimes accompanied by nausea, vomiting, photophobia, or altered mental status. Up to 20% of people with meningococcal disease present with meningococcal sepsis, known as meningococcemia. Meningococcemia is characterized by an abrupt onset of fever and a petechial or purpuric rash. The rash may progress to purpura fulminans. Meningococcemia often involves hypotension, acute adrenal hemorrhage, and multiorgan failure. Among infants and children aged <2 years, meningococcal disease may have nonspecific symptoms. Neck stiffness, usually seen in people with meningitis, may be absent in this age group.
Early diagnosis and treatment are critical. A lumbar puncture should be done to examine the cerebrospinal fluid (CSF) and perform a Gram stain. If possible, the lumbar puncture should be done before starting antibiotic therapy to ensure that bacteria, if any, can be cultured from CSF. Diagnosis is generally made by isolating N. meningitidis from blood or CSF, by detecting meningococcal antigen in CSF by latex agglutination, or by evidence of N. meningitidis DNA by PCR.
The signs and symptoms of meningococcal meningitis are similar to those of other causes of bacterial meningitis, such as Haemophilus influenzae and Streptococcus pneumoniae. The causative organism should be identified so that the correct antibiotics can be used for treatment and prophylaxis.
Meningococcal disease is potentially fatal and should always be viewed as a medical emergency. Antibiotic treatment must be started early in the course of the disease, and empirically prior to the diagnostic test results. Several antibiotic choices are available, including third-generation cephalosporins.
Indications for Use
The Advisory Committee on Immunization Practices (ACIP) recommends vaccination against meningococcal disease for people who travel to or reside in countries where N. meningitidis is hyperendemic or epidemic, particularly if contact with the local population will be prolonged. Hyperendemic regions include the meningitis belt of Africa during the dry season (December–June). Advisories for travelers to other countries are issued when epidemics of meningococcal disease caused by vaccine-preventable serogroups are recognized (see the CDC Travelers’ Health website at www.cdc.gov/travel). Note that proof of receipt of quadrivalent vaccination against meningococcal disease is required for people traveling to Mecca during the annual Hajj and Umrah pilgrimages.
Two quadrivalent meningococcal polysaccharide–protein conjugate vaccines are licensed for use in the United States: Menactra (Sanofi Pasteur) and Menveo (Novartis). A 1-dose primary series of Menactra is licensed for people aged 2–55 years; a 2-dose primary series of Menactra is licensed for children aged 9–23 months. Menveo is licensed for people aged 2–55 years. Quadrivalent meningococcal polysaccharide vaccine (Menomune, Sanofi-Pasteur) is licensed for use among people aged ≥2 years. These vaccines protect against meningococcal disease caused by serogroups A, C, Y, and W-135. No vaccine is available in the United States to prevent serogroup B meningococcal disease. Approximately 7–10 days are required after vaccination for development of protective antibody levels. Refer to Table 3-13 for more information about available meningococcal vaccines.
Menactra is the only meningococcal vaccine licensed for children aged 9–23 months. Either of the conjugate vaccines is preferred for people aged 2–55 years; polysaccharide vaccine should be used for people >55 years. In the United States, there is no licensed vaccine for children <9 months.
CDC recommends routine vaccination of people with conjugate vaccine at age 11 or 12 years, with a booster dose at age 16 years. For adolescents who receive the first dose at age 13–15 years, a one-time booster dose should be administered, preferably at age 16–18 years. People who receive their first dose at or after age 16 years do not need a booster dose, unless they remain at continued risk for meningococcal disease.
Travelers who were vaccinated previously and are living in or returning to Africa’s meningitis belt may need to be revaccinated. ACIP recommends that children previously vaccinated at ages 9 months through 6 years who remain at an increased risk for meningococcal disease receive an additional dose of conjugate vaccine 3 years after their previous meningococcal vaccine and every 5 years thereafter, if at continued risk. Likewise, people who were previously vaccinated at ages 7–55 years and who remain at an increased risk for meningococcal disease should receive an additional dose of conjugate vaccine 5 years after their previous dose and every 5 years thereafter, if at continued risk. Travelers aged >55 years should be vaccinated or revaccinated with polysaccharide vaccine if it has been >5 years since their last meningococcal vaccine. Previously unvaccinated travelers <56 years of age who have a history of complement component deficiency (C3, properdin, factor D, or late component), functional or anatomic asplenia, or HIV should receive a 2-dose primary series of conjugate vaccine, 8–12 weeks apart. For those aged ≥56 years with these conditions, a single dose of polysaccharide vaccine should be given before travel if possible.
Travelers to the Hajj must show proof of vaccination in the previous 3 years.
Vaccine Safety and Adverse Reactions
For polysaccharide vaccine, the incidence of local reactions (such as pain and redness at the injection site) has ranged from 4% to 56% across studies. Severe reactions are rare, with an incidence of <0.1 per 100,000 vaccinees. In comparison trials, the incidence of severe reactions after conjugate vaccination was similar to the incidence after polysaccharide vaccination; however, local reactions (including pain that limited movement of the arm of injection) were more common after conjugate vaccination.
Precautions and Contraindications
People with moderate or severe acute illness should defer vaccination until their condition improves. Vaccination is contraindicated for people who have severe allergic reaction to any component of the vaccines. People with dry natural rubber latex allergy should not receive Menactra. Polysaccharide vaccine is an acceptable alternative for protection against meningococcal disease in these people. All meningococcal vaccines are inactivated and may be given to immunosuppressed people.
In the United States and most industrialized countries, antibiotic chemoprophylaxis among close contacts of a patient with invasive meningococcal disease is recommended to prevent secondary cases. Chemoprophylaxis ideally should be initiated within 24 hours after the index patient is identified; prophylaxis given >2 weeks after exposure has little value. Antibiotic regimens for prophylaxis include rifampin, ciprofloxacin, and ceftriaxone. Ceftriaxone is recommended for pregnant women.
CDC website: www.cdc.gov/meningitis/bacterial.html
Table 3-13. Vaccines to prevent meningococcal disease
|VACCINE||TRADE NAME (MANUFACTURER)||AGE||DOSE||ROUTE||SCHEDULE||BOOSTER|
|Meningococcal polysaccharide diphtheria toxoid conjugate vaccine||Menactra (Sanofi Pasteur)||
0, 3 mo
|If at continued risk1|
|Meningococcal oligosaccharide diphtheria CRM197 conjugate vaccine||Menveo (Novartis)||2–55 y||0.5 mL||IM||1 dose||If at continued risk1|
|Meningococcal polysaccharide vaccine||Menomune (Sanofi Pasteur)||≥2 y||0.5 mL||SC||1 dose||If at continued risk2|
Abbreviations: IM, intramuscular; SC, subcutaneous.1Revaccination with meningococcal conjugate vaccine is recommended after 3 years for children who were previously vaccinated at ages 9 months to 6 years. Revaccination with meningococcal conjugate vaccine is recommended after 5 years for people who were previously vaccinated at ages 7–55 years, and every 5 years thereafter for people who are at continued risk.
2Revaccination with meningococcal polysaccharide vaccine is recommended for adults >55 years who remain at increased risk 3–5 years after the last dose.
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- Page last updated: August 01, 2013
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