Meningitis Spiked in 1990s
New strain, more virulent to young people, is suspected
TUESDAY, Aug. 7, 2001 (HealthDayNews) -- There were more cases of meningitis in the 1990s, and the infection was particularly virulent for people between the ages of 15 and 24, a study of the disease in Maryland reveals.
Researchers suggest that a newer version of the bacterium Neisseria meningitidis, the bug that causes both meningitis and blood poisoning, may have been the culprit. The number of cases of meningitis dropped at the end of the decade, implying that teenagers and young adults developed immunity to the stronger disease, they add.
"During the 1990s, the incidence of meningococcal disease went up among adolescents and young adults, and by the peak, almost 30 percent of all cases of meningococcal disease in Maryland were in adolescents and young adults," says the study's author, Dr. Lee Harrison, an associate professor of epidemiology at the University of Pittsburgh. "And about 23 percent of them died, which was unexpectedly high."
Harrison and colleagues at Johns Hopkins University School of Medicine -- where he is also an adjunct professor -- looked at all incidents of meningitis from 1990 through 1999 in the state of Maryland. Of the 295 cases, 71 involved adolescents and young people between the ages of 15 and 24, and 16 of those cases proved fatal. "That was an annual incidence rate increase from 0.9 to 2.1 cases per 100,000," Harrison says.
Meningitis strikes about 3,000 Americans every year and causes more than 300 deaths. Officials estimate that 100 to 125 cases of the disease occur annually on college campuses and five to 15 students die as a result. The bacteria are spread through air droplets or contact with infected victims, most often in late winter and early spring. Meningitis often attacks the brain and spinal cord and can result in permanent brain damage, hearing loss, learning disability, organ failure, loss of limbs as well as death.
In Maryland, meningitis was more likely to be fatal for 15-to-24 year-olds (22.5 percent) than those younger than 15 (4.6 percent), Harrison reports. And the meningitis vaccine could have prevented approximately 82 percent of those fatalities in 15-to-24 year-olds, he adds.
As Maryland goes, so goes the nation. "The disease strain was not particular to Maryland," Harrison says. "We do know that multiple other sites have seen similar increases around the nation."
"The thing we hypothesize in this paper is that the disease may have been due to [a new] circulating strain causing the disease," Harrison explains. "We are trying to DNA fingerprint [the bacterium] at this point in order to see if that is true, though that's not known yet. And the drop of the cases at the end of the decade was not due to increased vaccination," he says. "If our hypothesis that there was a new strain holds true, then probably what happened is that the general population developed immunity."
The findings appear in the Aug. 8 issue of the Journal of the American Medical Association.
Lots of people carry the meningitis bacteria and don't know it, says Dr. Randy Rock, associate director of health education at the University of Kansas' Watkins Memorial Health Center and a spokesman for the Meningitis Foundation of America. "The body may host the bacteria in the oral pharynx, and it may be of no consequence. At any given time, 10 percent of the population may host this bacteria and it doesn't result in illness."
"It is not fully understood why meningitis becomes invasive," Rock says, "and luckily it's very rare."
But dormitory living seems to be a risk factor for the disease, he adds.
"Studies suggest that certain conditions may predispose certain young adults to greater risk of developing invasive disease," he explains. "Those would include living in dormitories, alcohol consumption and cigarette smoking. In combination, those lifestyle choices and frequent close contact with others probably define [the] increased risk for developing meningitis."
What To Do
Vaccination is the solution.
"For those who wish to reduce their risk, they should be considering the vaccination," Rock says. "In our experience, there have been limited local reactions, such as a swelling at the site of the injection. But in general the vaccination is considered to be quite safe."