Hearing Aids Linked to Meningitis

Vaccination Urged for Patients With Cochlear Implants

Reviewed by Paula M. Elbirt, MD
From the WebMD Archives

July 25, 2002 -- Nine people have died from a deadly infection linked to hearing devices called cochlear implants, the FDA warns. At least 25 children and adults worldwide have developed bacterial meningitis after receiving the implants.

Three companies manufacture the devices. So far, two of these companies have reported cases among patients who received their brands of the device.

The FDA says that an ongoing, urgent survey of cochlear implant centers suggests that "there are additional, unreported cases of meningitis in the cochlear implant population." About 60,000 people worldwide have cochlear implants.

People who have the implants should consider getting vaccinated against the kinds of germs that most often cause bacterial meningitis. The FDA says that everyone with an existing implant or who is about to get one should check to see whether they already have been vaccinated.

Meningitis is an infection of the fluid and tissue surrounding the brain and spinal cord. Bacterial meningitis is generally considered more severe than the viral form.

Cochlear implants aren't your average hearing aid. Designed for people with deafening nerve damage, the devices are surgically implanted deep within the ear. They turn sound waves into electric signals that are passed to nerve fibers leading into the brain. The devices have restored hearing to many people who cannot be helped by other types of hearing aids.

Exactly why a cochlear implant might be linked to bacterial meningitis is unknown. The device itself appears to be germ free. The implant goes close to the brain, but it seems unlikely that the device itself is creating a new pathway for germs. It seems more likely that germs invading the inner ear can cluster on the device and then get into the bloodstream.

A single kind of germ -- pneumococcus -- causes nearly all cases of bacterial meningitis. Of the 11 cochlear-implant cases of meningitis analyzed so far, seven are definitely and four are "most likely" pneumococcus.

There's already an effective pneumococcal vaccine. There's one version for adults and children age 2 years and older. Another form of the vaccine (Prevnar) can be given to children as young as 2 months old. Because Prevnar is relatively new -- it hit the market in March 2000 -- many children remain vulnerable. The CDC already recommends this vaccine for all children.

These cases of bacterial meningitis often occurred a year or more after implantation. This suggests that vaccination of all children and adults who get cochlear implants might protect them from getting bacterial meningitis.

Pneumococcal infection often begins in the middle ear. The link between implants and meningitis means that people with implants -- particularly children and elderly adults -- should get immediate and aggressive treatment for all ear infections.