Meningitis Rate Is Dropping in U.S.

May 25, 2011 -- Cases of bacterial meningitis continue to decline in the U.S., with incidence falling by almost a third over the last decade, the CDC says.

The latest drop is being attributed in part to the introduction of the pneumococcal conjugate vaccine, which protects children from a leading cause of bacterial meningitis, Streptococcus pneumoniae.

It follows an even bigger decline in cases over the previous decade, which saw the introduction of a vaccine targeting Haemophilus influenza type B (Hib). Between the mid-1980s and mid-1990s, bacterial meningitis cases in the U.S. dropped by 55%.

The CDC report appears in tomorrow's New England Journal of Medicine.

"The good news is that this very serious infection is now a lot less common than it was," CDC chief of bacterial and respiratory diseases Cynthia Whitney, MD, MPH, tells WebMD.

"But we want people to know that this disease does still occur. There are about 4,000 cases of bacterial meningitis each year in the U.S., so physicians still need to be aware of the signs and treat patients quickly and aggressively."

Meningitis Can Be Fatal Quickly

While there has been great progress in preventing bacterial meningitis, far less progress has been made in treating the disease once people get it, Whitney says.

If not treated quickly, bacterial meningitis can sometimes progress from first symptoms to death in less than a day.

In April, a 21-year-old college student in New Hampshire with a rare form of bacterial meningitis died just 12 hours after seeking medical treatment for a severe headache and rash, according to news reports.

And last spring, two students at an elementary school in Oologah, Okla., died and four others were hospitalized with bacterial meningitis within days of first complaining of symptoms.

High fever, headache, and neck stiffness are the most common symptoms of bacterial meningitis in adults and children over the age of 2.

"When people get bacterial meningitis, it still tends to be very serious," Whitney says.

Biggest Drop Occurred in Babies

CDC researchers analyzed bacterial meningitis incidence data between 1998 and 2007, concluding that about 4,100 cases and 500 deaths occurred annually between 2003 and 2007.

Among the other findings:

• Bacterial meningitis declined by 31% during the survey period, down from about two cases per 100,000 people in 1999 to 1.4 cases per 100,000 people in 2007.
• The average age of bacterial meningitis patients increased from about 30 to 42 during the period.
• The death rate did not decline significantly: roughly 16% of patients with bacterial meningitis in 1999 died, compared to 14% of patients in 2007.
• Among children 2 to 23 months old, incidence declined from close to 10 cases per 100,000 in 1999 to less than four in 2007.

"With the success of pneumococcal and Hib conjugate vaccines in reducing the risk of meningitis among young children, the burden of bacterial meningitis is now borne more by older adults," the CDC report notes.

Infectious disease specialist William Schaffner, MD, of Vanderbilt University Medical Center in Nashville, Tenn., says experimental vaccines now in the pipeline may lower incidence even further among infants and children in the future.

"With the average age of people with meningitis rising, the next challenge will be to prevent it from occurring in adults, particularly seniors," he tells WebMD.

College-Bound Teens Need Booster

There are also concerns that vaccines targeting meningococcal meningitis may not be protecting teens at a particularly vulnerable time -- when they enter college.

Meningococcal meningitis is the form of the disease most often associated with outbreaks in colleges.

Last fall, a federal vaccine advisory committee recommended that 16-year-olds be given booster doses of the vaccine due to concerns that immunity from immunization at age 11 or 12 does not last into the college years.

The recommendation was somewhat controversial, but Schaffner says a booster shot is a good idea for teens entering college.

"This is a horrific disease that can kill quickly," he says. "As a doctor who has treated young people with bacterial meningitis, I wouldn't hesitate to recommend a booster vaccine to prevent it."