Rates of Meningococcal Disease in Military Plummet

SAN DIEGO — Meningococcal disease among U.S. military personnel plummeted by more than 90% from 1971 to 2010 because of the introduction of three successive vaccines during the time period, according to a new study.1

That means that the rate of meningococcal disease now is similar to that observed in the general U.S. population, according to Michael P. Broderick, PhD, from the Naval Health Research Center in San Diego and colleagues whose report appeared earlier this year in the Emerging Infectious Diseases.

Historically, rates of meningococcal disease have been higher in the military than in the general population, often because of crowding and unhygienic conditions, according to the study. It noted that, during World War I, the incidence of meningococcal disease was 150 per 100,000 person-years compared to 9 per 100,000 in the general population, and that during World War II, it was 80 per 100,000 person-years in contrast to 16 per 100,000 in the general population.

“After the U.S. Army’s early 1970s introduction to all incoming personnel of a vaccine targeting [ Neisseria] meningitidis serogroup C, disease rates dropped by >90%,” the authors noted. “However, during 1971-1989, the Army’s mean annual incidence remained significantly higher than that among the non-age-matched general population,” with an incidence of 3.6 compared with 1.02 in the general population.

Only after the introduction of a quadrivalent polysaccharide vaccine, MPSV-4 ( Menomune, Sanofi Pasteur) in 1982 did meningococcal disease among the military drop to rates similar to those observed in the general population — 0.5 vs. 0.7.

“Of particular interest is the performance of the newer conjugate vaccine, MCV-4 (Menactra; Sanofi Pasteur), which gradually replaced MPSV-4 in the military during 2006–2008,” the authors wrote.

In the current report, 26 cases, all but one confirmed, of meningococcal disease that occurred in the U.S. military from 2006 to 2010 are described. Of those, five were fatal, 15 occurred in servicemembers who had been previously vaccinated and nine were caused by N meningitidis serogroup Y, the report said, citing data from the Armed Forces Health Surveillance Center Defense Medical Surveillance System database and the EpiData Center at the Navy and Marine Corps Public Health Center.

The mean incidence of meningococcal disease for US military branches was lowest for the Air Force, at 0.120 and reached a high of 1.353 for the Marine Corps. Incidence also was significantly higher among 17- to 19-year-old basic trainees and among Marines was significantly higher than among comparison military populations.

No cases occurred in the military in the 34- to 39-year and older-than-40-years age ranges.

“In the military setting, and especially in the basic training setting, epidemic meningococcal disease remains controlled due to a robust immunization program,” the authors conclude, adding that “no evidence of a change in overall disease rates has been associated with the switch to MCV-4 vaccine. However, the increase of serogroup Y infections among the military population warrants further observation.”

  1. Broderick MP, Faix DJ, Hansen CJ, Blair PJ. Trends in meningococcal disease in the United States military, 1971-2010.   Emerg Infect Dis. 2012 Sep;18(9):1430-7. doi: 10.3201/eid1809.120257.  PubMed PMID: 22932005; PubMed Central PMCID: PMC3437735.

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