Update on Meningitis Risk from Cochlear Implant

Editor: About a year ago there were reports of links between cochlear implants (CIs) and meningitis. At that time it seemed that the positioner used by Advanced Bionics was that cause, and that CIs that didn't use the positioner didn't increase the risk of meningitis.

Now it seems there may be more to the story. The Center for Disease Control and Prevention is reporting that CIs in general result in an increased meningitis risk, at least for children. Here are portions of the press release.

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United States Department of Health and Human Services
Centers for Disease Control and Prevention
Office of Communication
Division of Media Relations

Press Release

July 30, 2003, 5:00 p.m. ET

Contact: CDC Media Relations (404) 639-3286

Children with Cochlear Implants at Increased Risk for Bacterial Meningitis

CDC offers recommendations to decrease a child's risk of developing the illness

Children with a cochlear implant have a greater risk of developing pneumococcal (Streptococcus pneumoniae) meningitis compared to children in the general population, according to a study conducted by the Centers for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA) and others published in the July 31 issue of The New England Journal of Medicine (NEJM). Additionally, children with a specific type of cochlear implant that had an extra piece called a "positioner" had 4.5 times the risk of developing meningitis compared to recipients of other cochlear implant types. The manufacturer voluntarily recalled the device with the positioner last year.

The CDC and FDA began investigating this possible link between the implants and meningitis in the summer of 2002 after receiving reports of bacterial meningitis among recipients of cochlear implants. As soon as the FDA became aware of a possible association between cochlear implants and bacterial meningitis, the agency issued a public health Web notice and began working with manufacturers of cochlear implants to determine the nature and scope of the problem. As a result, the company that made the implant with the extra positioner voluntarily withdrew that product from the market.

[snip]

The study authors note that individuals who are candidates for cochlear implants may have factors that increase their risk of meningitis compared to the general population even prior to being implanted with the device. However, the study was not designed to determine the risk due to these preexisting factors.

"These findings have important implications for children with cochlear implants. Most bacterial meningitis is vaccine-preventable so children who have a cochlear implant, or who will receive one, should have all recommended childhood vaccinations, including age-specific pneumococcal vaccinations for high-risk children," said Dr. Julie Gerberding, CDC Director.

[snip]

Nearly 10,000 children and 13,000 adults in the United States with severe-to-profound hearing loss have a cochlear implant. The implant is an electronic device containing electrodes that are surgically inserted into the cochlea (inner ear) to activate nerve fibers and allow sound signals to be transmitted to the brain. It can help children with hearing loss perceive sounds and learn to speak.

The study group involved 4,264 children who received a cochlear implant in the United States between January 1, 1997 and August 6, 2002, and who were younger than age 6 at the time of the implant.

A total of 29 cases of bacterial meningitis were identified in 26 children (three children had two episodes of the illness). Fifteen children had meningitis caused by Streptococcus pneumoniae. Less than one case of the disease would be seen in a group this size, during the same time period, based on the rates in the general population.

Nine of the 29 cases occurred within a month following the cochlear implant surgery, the remaining 20 occurred up to 36 months later.

"Cochlear implants have been of great benefit to many profoundly deaf children who were previously unable to hear sound of any kind. When considering an implant for their child, parents need to discuss the findings of this investigation with their child's physician," says Jennita Reefhuis, Ph.D, the study's lead author. "Parents of children with any type of cochlear implant should watch carefully for any signs of bacterial meningitis, which include high fever, stiff neck, nausea or vomiting, sleepiness or confusion, and seek prompt medical attention if the symptoms occur."

CDC's Advisory Committee on Immunization Practices (ACIP) makes the following recommendations for children who have or may receive cochlear implants: Physicians and parents of children who have received cochlear implants should review the child's vaccination status and make sure he or she is up-to-date for age on pneumococcal vaccinations according to schedules used for children at high risk and on Haemophilus influenzae type b (Hib) vaccinations;

Children should be up-to-date for age on vaccinations at least two weeks prior to cochlear implant surgery, if possible;

Physicians should assist parents in weighing the benefits and risks of cochlear implant surgery.

This study did not compare rates of bacterial meningitis among the cochlear implant group compared to that of deaf children without cochlear implants. However, Reefhuis says there are several follow-up projects underway. "Because Denmark has an excellent data-collection system for answering this question we are working with our Danish colleagues to obtain an estimate of the bacterial meningitis rate among children with hearing loss who do not have cochlear implants. In addition, we are continuing to track new cases of meningitis in this country that occur in cochlear implant recipients." Reefhuis says results from the Danish study should be available by early 2004.

The full ACIP recommendations will be available at 8:00 a.m. ET, Thursday, July 31 at http://www.cdc.gov/mmwr/preview/mmwrhtml/m2e731a1.htm.