Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.See all posts »
Update on Vaccine Against Meningococcus
Menactra is approved for use in protecting children against meningococcus.
One of the most feared infectious diseases for outdoor travelers—particularly children and young adults—meningitis caused by the bacterium Neisseria meningitidis (meningococcus). The infection can appear in outbreaks, most commonly abroad, particularly in sub-Saharan Africa and China. The infection is spread in the respiratory secretions of humans.
The disease appears in many forms, the most common of which are meningitis, pneumonia, and disseminated bacterial infection. The typical presentation of meningitis is fever, headache, and a stiff neck. If the cause is meningococcus, the victim may develop a skin rash, which consists of red dots or bumps, or a flat, more patchy dark red discoloration. If the dark red dots begin to enlarge and coalesce into large purplish bruise-like discolorations, this is a bad sign. In the worst cases, a victim can develop shock, respiratory failure, diffuse bleeding, and death. Approximately one in 10 victims of meningococcal meningitis dies.
Meningococcal meningitis is a true emergency. The victim needs large doses of intravenous antibiotics, such as ceftriaxone. If these are not available, one may administer a high oral dose of penicillin, cephalexin, cefixime, cefpodoxime, or amoxicillin–clavulanate acid for 10 days. If the victim is allergic to penicillin, then trimethoprim-sulfamethoxazole or ciprofloxacin can be used.
Ciprofloxacin may also be administered to all close (“household”) contact adults in a single dose of 500 mg in order to stave off potential infection. Azithromycin in a single dose of 500 mg by mouth may also be effective for prophylaxis against the disease in contacts. Rifampin may also be used for this purpose in adults (600 mg a day by mouth for two days) and children (<1 month: 5 mg/kg by mouth every 12 hours for 2 days; >1 month: 10 mg/kg by moutth every 12 hours for 2 days). A physician may elect to prescribe an injection of ceftriaxone for this purpose as well.
Even with appropriate antibiotics and intensive care, between 10 and 15 percent of people who develop meningococcal disease die from the infection. Another 10 to 20 percent suffer complications such as brain damage or loss of limb or hearing.
The Vaccine Against Meningococcus
It is a wise idea for travellers to Nepal—particularly hikers and backpackers—to be immunized with Menactra, which is a tetravalent vaccine used to prevent meningococcal meningitis caused by Neisseria meningitidis serogroups A, C, Y and W-135. Certain areas of sub-Saharan Africa are also considered high risk from December to June. Domestically (within the U.S.), the vaccine is recommended for children aged 11 to 12 years during their regular healthcare visit, and if at all possible prior to entry into college.
The big news is that the U.S. Food and Drug Administration (FDA) has just approved the use of Menactra in children as young as age nine months old for the prevention of invasive meningococcal disease.
From the FDA announcement:
Although the rates of meningococcal disease are low in the United States, infants and toddlers are more susceptible to getting this serious illness. Meningococcal disease is particularly dangerous because it progresses rapidly and can cause death within hours. Early symptoms are often difficult to distinguish from influenza and other common illnesses. ‘The highest rate of meningococcal disease occurs in children under one year of age. With today’s approval, Menactra can now be used in children as young as nine months of age to help prevent this potentially life-threatening disease,’ said Karen Midthun, M.D., director of FDA's Center for Biologics Evaluation and Research. The safety of Menactra in children as young as 9 months was evaluated in four clinical studies in which over 3,700 participants received the vaccine. The most common adverse events reported in children who received Menactra at nine months and 12 months of age were injection-site tenderness and irritability. Occurrence of fever was comparable to other vaccines routinely recommended for young children.”
For children under two years of age, Menactra is given as a two-dose series beginning at nine months, three months apart; the study results showed that the vaccine produces antibodies in the blood that are protective against the disease. For persons ages two years and older, it is given as a single dose, and protection for five years is attained only one to two weeks after injection.
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