About the 2002 Study

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Background

In summer 2002, the U.S. Food and Drug Administration (FDA) began receiving reports of bacterial meningitis occurring among people who had cochlear implants. In response, the Centers for Disease Control and Prevention (CDC), with the FDA and the health departments of 36 states, the District of Columbia, Chicago, and New York City, began an investigation.

Conducting the Study

The purposes of the study were (1) to find out how many children who had cochlear implants got bacterial meningitis afterwards and (2) to find out what factors might make it more likely that someone would get meningitis after getting a cochlear implant. The study was limited to children who were 6 years of age or younger when they got their implant because the majority of cases reported were in children in this age group, and because children in this age group will receive most implants in the future. Children who had received their implant during the period from January 1, 1997, through August 6, 2002 were included. Potential cases of bacterial meningitis were identified from reports to implant manufacturers, the FDA Adverse Events Reporting System, and CDC and state and local health department tracking systems. In addition, study researchers contacted the parents of all the children in this group to ask them if their child had been seriously ill since getting the implant.

Some Basic Facts About the Study

• A total of 4,262 children 6 years of age or younger received a cochlear implant during the period from January 1, 1997, through August 6, 2002. This large study group was used to estimate how many of the children with cochlear implants got bacterial meningitis. This number was then compared with the number of children of this age in the general population who got bacterial meningitis.

• A smaller study group was used to find what factors made it more likely for someone with an implant to get meningitis. This smaller study was made up of all 26 children with confirmed bacterial meningitis and a random sample of 200 children with implants who did not get bacterial meningitis after receiving the implant.

• Detailed interviews of parents were done only for the small study group. A review of medical records was also done.

• The study was limited to children who received their cochlear implants in the United States.

Study Findings and Conclusions

The study found that:

• Bacterial meningitis occurred more often in children with all types of cochlear implants than in children of the same age group in the general population.

• The majority of cases of meningitis were caused by S. pneumoniae, a type of bacteria.

• Children with an implant with a positioner were much more likely to get bacterial meningitis than children with other types of cochlear implants. (The implant with a positioner was voluntarily taken off the market by the manufacturer in July 2002.)

• Because the study was not able to find out how the positioner increased the risk for bacterial meningitis, it was not clear whether removing the implant would lower the risk and we cannot make recommendations about that. The removal procedure could place the child at risk for meningitis or other related complications following surgery.

• Children with a cochlear implant who had inner ear malformations and cerebrospinal fluid leaks were at increased risk for bacterial meningitis.

Recommendations

• Children should be up to date on vaccines at least 2 weeks before having a cochlear implant if they are not already up-to-date on these vaccinations. (Specific vaccine recommendations for children with cochlear implants are included in the Questions and Answers.)

• Parents of children who have already received an implant should check with their child’s doctor to ensure that their child is up to date on all vaccinations.

• Doctors and other health care providers should review vaccination records of their patients who are cochlear implant recipients or candidates to ensure that they have received pneumococcal vaccinations based on the age-appropriate schedules for high risk people and that they have received age-appropriate Hib vaccinations.

• Parents of children with cochlear implants should be watchful for possible signs and symptoms of meningitis (which are listed in the Questions and Answers) and seek prompt attention for any bacterial infection their child might have. Any questions parents have about their child’s health should be discussed with the child’s doctor.

• Parents of children with cochlear implants should also be watchful for signs and symptoms of an ear infection, which can include ear pain, fever, and decreased appetite.

• Parents should seek prompt medical attention for any possible ear infections.

• Parents should talk about the risks and benefits of cochlear implants with their child’s doctor and should discuss whether their child has certain medical conditions that might make him or her more likely to get meningitis.

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Date: October 27, 2006
Content source: National Center on Birth Defects and Developmental Disabilities