The meningococcal ACWY conjugate vaccine (MCV) is a vaccine to protect against disease caused by four strains of the bacterium Neisseria meningitidis, or simply meningococcus.
The disease
Meningococcus causes very serious and often fatal disease in humans. It usually causes either meningitis, blood infection, or both. Blood infection is actually often more severe than meningitis, though either can be deadly. The germ strikes healthy children and adults without warning, is contagious, and progresses rapidly, often before treatment can be started. Even when antibiotics are given, it often leads to death or permanent disability. For these reasons, these are the cases of meningitis that are reported in the news. It often strikes healthy teenagers or young adults, and close contacts are treated with antibiotics to keep them from catching it.
Between 1,500 and 3,000 people in the United States are infected with meningococcus every year; about 10-15% of them die (it kills about 300 people a year in the U.S.), and up to 20% of survivors have permanent disabilities (brain damage, deafness, amputation of arms and legs). It is the now most common cause of bacterial meningitis in children. The greatest rate of infection occurs in infants less than one year of age; the risk rises again around age 15 and continues through age 24. College freshmen living in dorms are at a particularly high risk.
For decades a polysaccharide vaccine has been available; however, it is not as effective or long-lasting as other vaccines. It has been used in college freshmen and military recruits and during outbreaks. The vaccine, because of the kind of vaccine it is, is particularly ineffective in young children at providing immunity. Conjugate vaccines, like the HIB and PCV vaccines, are much more effective and long lasting, and a meningococcal conjugate vaccine was developed against the 4 most common strains in 2005.
The vaccine
The meningococcal conjugate vaccine became available in 2005 and is marketed as Menactra®. It became part of the recommended immunization schedule a month after it was approved by the FDA. It is currently approved and recommended for all children ages 11 and up. A booster dose as been added at age 16. Many colleges are requiring the vaccine before starting the freshman year.
Side effects
The most common side effects are local reactions at the injection site, including pain and redness for a day or two, and mild headache or malaise within 7 days of receiving the vaccine. Some report arm soreness for a day or two after the vaccine. About 3% of recipients have fever within 7 days of receiving the vaccine. Fever is not a common side effect. There are not any known severe side effects or risks of the vaccine.
Risks vs. benefits
The vaccine is very effective at preventing disease due to the most common strains of meningococcus, though it does not protect against type B, which is common in some populations and can cause outbreaks. The disease is not that common compared with other diseases, but it strikes without warning, is often deadly even when treated with antibiotics, and children are particularly susceptible to the disease. The vaccine does not have any known serious side effects. As a parent and a pediatrician, I am very thankful for this vaccine and highly recommend it.
Resources
Meningococcal ACWY (MenACWY) Vaccine Information Statement (CDC)
References
Prevention and Control of Meningococcal Disease MMWR, March 22, 2013, Vol 62, #RR02
Published April 15, 2005. Last revised November 5, 2016
