WEDNESDAY, May 25 (HealthDay News) -- The incidence of bacterial
meningitis dropped by 31 percent between 1998 and 2007, new
government research shows.
The drop was led by reductions in infections by two powerful
Neisseria meningitidis and
Streptococcus pneumoniae -- that are covered by available
immunizations. With fewer infections among young children, the
burden of the disease is now mainly borne by older adults, the
study authors found.
"The good news is that fewer people are getting bacterial meningitis. The bad news is that if you get it, it's still a very serious infection," said study co-author Dr. Cynthia Whitney, chief of the bacterial respiratory diseases branch at the U.S. Centers for Disease Control and Prevention in Atlanta.
"There are still at least 4,000 cases a year, including about 500 that are fatal," she noted.
Results of the study are published in the May 26 issue of the
New England Journal of Medicine.
Bacterial meningitis is a dangerous bacterial infection that
causes inflammation of the membranes that cover the brain and
spinal cord, according to the CDC.
Signs of meningitis in people over the age of 2 include fever,
headache and stiff neck, according to the CDC, while symptoms in
newborns and infants can include fever, seizures, constant crying,
a bulge in the soft spot on the head and stiffness in the body and
neck. Bacterial meningitis can be contagious.
The five types of bacteria that were most responsible for
bacterial meningitis in the 1970s and 1980s were
S. pneumoniae, group B streptococcus and
Listeria monocytogenes, according to the study.
In the late 80s and early 90s, the incidence of bacterial
meningitis dropped by 55 percent, likely because an infant vaccine
was introduced in 1990 for
H. influenzae type B (Hib).
Since that time, other vaccines have been introduced for strains
N. meningitidis and
S. pneumoniae that appear responsible for the shrinking
infection rate caused by those germs. The rate of one type of
S. pneumoniae decreased by 92 percent during the study
period, and the incidence of
N. meningitidis dropped by 58 percent.
The findings were based on information from the CDC's Emerging
Infections Programs Network, which included eight surveillance
sites across the United States. These sites include data on about
17.4 million people.
During the surveillance period between 1998 and 2007, the
incidence of bacterial meningitis dropped from two cases per
100,000 people to 1.38 cases per 100,000 people. The average age of
those affected increased from 30.3 years to 41.9 years.
The incidence of meningitis was highest among blacks and
children under 2 months old throughout the study period, the CDC
In addition, rates of death caused by bacterial meningitis
didn't change significantly over the study period. Among adults,
those aged 65 or older were most likely to die from the
The youngest and oldest people are typically more susceptible to
infections from a variety of causes, but Whitney said that the CDC
researchers aren't sure why blacks have significantly higher rates
of bacterial meningitis.
Kenneth Bromberg, director of the Vaccine Study Center at the
Brooklyn Hospital Center, said it can be difficult to tease out the
reasons why certain groups have higher rates of some infections: Is
it an inherent susceptibility? Is it an access-to-care issue? In
this case, he said he thinks that black people may have a genetic
susceptibility to certain bacteria that cause meningitis.
There are three different types of vaccines available for
bacterial meningitis. These vaccines don't cover every strain that
can cause meningitis, but they do offer protection against many of
the common strains. The Hib vaccine, which covers
H. influenzae, is part of routine childhood immunizations.
The meningoccocal vaccine (MCV4), which protects against
N. meningitidis, covers against a form of bacterial meningitis that is often passed from person-to-person when many people are living in close quarters, such as a college dormitory or military barracks. The CDC recommends the first dose of this vaccine be given at 11 to 12 years old, and then a booster at 16 years old; it's also recommended for certain high-risk children aged 2 through 10. If you're over 16 when you first receive this vaccine, the CDC says only one dose is needed.
The pneumococcal vaccine (called PCV-13 for children and PPSV in
adults) is part of routine childhood immunizations. People who are
at higher risk of developing bacterial meningitis may receive a
booster dose. In addition, people who are over 65, or younger
people who have chronic health conditions or a compromised immune
system, should also receive this vaccination, as should anyone who
smokes or has asthma, despite their age, according to the CDC.
"Public health surveillance like this is exceedingly important in evaluating our public health strategies. It's good to see that the rates of bacterial meningitis are going down, but the death rate has not gone down for those who do have it," noted Bromberg.
"The good news is that we're doing something to prevent bacterial meningitis, and we've made a lot of strides in the past decade. But, physicians and patients need to know that bacterial meningitis still occurs and it is still a deadly serious infection," Whitney said.
Besides getting immunized, Whitney noted that staying healthy
and not smoking can help keep your immune system primed to fight
off these infections. She said it's also important to note that
Listeria is a significant cause of meningitis, and that
pregnant women need to be especially careful about the foods that
they eat to avoid this infection.
To learn more about bacterial meningitis, visit the
U.S. Centers for Disease Control and
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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