Canada Communicable Disease Report
Volume 29 ACS-2
1 April 2003

An Advisory Committee Statement (ACS) 
National Advisory Committee on Immunization (NACI)*^†

IMMUNIZATION RECOMMENDATIONS
FOR COCHLEAR IMPLANT RECIPIENTS

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Background 

In July 2002, Health Canada became aware of a possible association between receipt of a cochlear implant and development of bacterial meningitis. At that time, approximately 30 cases had been reported in Europe and the United States, and one case had been reported in Canada. As of 17 October, 2002, the Food and Drug Administration was aware of 91 reports of meningitis in patients with cochlear implants worldwide, 17 (19%) of which were fatal. Laboratory results are available for 23 of the 52 U.S. cases: 16 were positive for Streptococcus pneumoniae, four for Haemophilus influenzae (type not available), two for viridans group streptococci, and one for Escherichia coli⁽¹⁾. 

Worldwide, there are three manufacturers of cochlear implants, all of whom have reported cases of bacterial meningitis in their implant recipients. More than 60% of international cases had received cochlear implants from one specific manufacturer, Advanced Bionics Corporation. When the problem was first recognized in Canada, two manufacturers were licensed to sell cochlear implants: Advanced Bionics Corporation (licensed in 1994) and Cochlear Corporation (licensed in 1987). A third manufacturer, Med-EL Corporation, became licensed in October 2002. In late July 2002, Advanced Bionics Corporation conducted a worldwide, voluntary recall of their cochlear implant product. In Canada, this occurred on July 26, 2002. 

Since the first cochlear implant device was licensed in Canada in 1987, approximately 2,000 devices have been implanted; approximately 30% were Advanced Bionics Corporation products, and the remainder were Cochlear Corporation products. As of November 19, 2002, five cases of bacterial meningitis in cochlear implant recipients had been reported to Health Canada, one of which was fatal. Cases ranged in age from 5 to 65 years (three cases were < 17 years of age). Onset dates were between November 1999 and August 2002, and the interval between receipt of implant and onset of meningitis ranged from 4.5 months to 4.25 years (four cases had intervals < 1 year). The causative organisms were S. pneumoniae (three cases), group B streptococcus (one case) and H. influenzae type f (one case). Three cases had an Advanced Bionics Corporation product, and two had a Cochlear Corporation product. 

The mechanism of infection for bacterial meningitis in cochlear implant recipients has not yet been established. The cochlear implant itself, because it is a foreign body, may act as a nidus for infection. Other predisposing factors may include congenital abnormalities of the cochlea (e.g. Mondini's malformation); deafness secondary to a previous episode of meningitis; young age; otitis media; immunodeficiency; and surgical technique. An additional hypothesis is that the design of the electrodes with positioners featured in the HiFocus I and HiFocus II Clarion products manufactured by Advanced Bionics Corporation may be a predisposing factor. Cochlear Corporation and Med-EL Corporation electrodes do not have positioners. 

Health Canada is conducting investigations into the potential association between receipt of a cochlear implant and the subsequent development of bacterial meningitis. Health Canada initiated enhanced surveillance of bacterial meningitis in July 2002, and this remains ongoing. As well, Health Canada is conducting a retrospective cohort study of all cochlear implant recipients in Canada who received their implants since 1995. The objectives of this study are to (1) determine rates of bacterial meningitis among the cochlear implant population; (2) determine whether the risk of bacterial meningitis among cochlear implant recipients is related to the type of cochlear device used and/or the manufacturer of the device; and (3) recommend appropriate public health action based on the results of the investigation. The results of this investigation should be available early in 2003. 

NACI Recommendations 

Pneumococcal Vaccine 

People with cochlear implants or those who are receiving cochlear implants should be considered at high risk for invasive pneumococcal disease and should receive pneumococcal vaccine according to the schedule for individuals at high risk^(2,3) (Table 1). 

Children >= 5 years of age with high-risk conditions who have not previously received pneumococcal vaccines should be vaccinated with PPV23 as per previous NACI recommendations⁽³⁾. Prevnar®, the current PCV7, is licensed in Canada for children < 9 years of age. PCV7 is not contraindicated in children >= 5 years of age with high-risk conditions. When circumstances permit, the conjugate vaccine may be given as the initial dose followed by the polysaccharide vaccine to provide additional serotype coverage and as a booster. If both PCV7 and PPV23 are used, the administration of each should be separated by at least 8 weeks. One revaccination should be considered 3 to 5 years after the first dose for children a) who are immunocompromised, have sickle cell disease, or suffer from functional or anatomic asplenia; and b) who are also < 10 years of age at the time of the first PPV23 vaccination^(2,3). 

Table 1.    Schedule for pneumococcal vaccine in individuals at high risk 

Haemophilus influenzae Type b (Hib) 

People with cochlear implants or those who are receiving cochlear implants should be considered at high risk for invasive disease caused by H. influenzae type b and should receive Hib vaccine according to the following routine schedule⁽³⁾ (Table 2). 

Table 2.    Schedule for Hib conjugate vaccine 

Note: There are three conjugate Hib vaccines licensed in Canada for infants >= 2 months of age: PRP-T (Act-HIB™ by Aventis Pasteur); HbOC (HibTITER™ by Wyeth Ayerst); and PRP OMP (Pedvax HIB™ by Merck Frosst). A fourth Hib conjugate vaccine, PRP-D (ProHIBIT™ by Connaught) is licensed for use only in children >= 18 months of age. ProHIBIT is currently not recommended in Canada because it induces antibody responses that are suboptimal compared with other Hib conjugate vaccines⁽³⁾. 

For previously unimmunized high risk adults and children >= 5 years of age the efficacy of Hib immunization is unknown. Despite limited efficacy data, Hib vaccine is commonly given to those with anatomic or functional asplenia and may be considered for other people at increased risk of invasive Hib infection⁽³⁾.

Meningococcal Vaccine 

People with cochlear implants or those who are receiving cochlear implants are not currently considered at high risk for invasive meningococcal disease. However, NACI recommends meningococcal C conjugate vaccine for routine immunization of all infants, children aged 1-4 years, adolescents, and young adults. For children >= 5 years of age who have not reached adolescence, immunization with a single dose of meningococcal C conjugate vaccine may also be considered^(3,4). 

References 

1. FDA Public Health Web Notification. Cochlear implant recipients may be at greater risk for meningitis. URL: http://www.fda.gov/cdrh/safety/cochlear.html 24 July, 2002, updated 17 October, 2002. Accessed 10 December, 2002. 

2. National Advisory Committee on Immunization. Statement on recommended use of pneumococcal conjugate vaccine. CCDR 2002;28(ACS-2):1-32. 

3. National Advisory Committee on Immunization. Canadian  immunization guide, 6^th ed. Ottawa (Ontario): Health Canada, 2002;177-84 (Minister of Public Works and Government Services, Cat. No. H49-8/2002E). 

4. National Advisory Committee on Immunization. Statement on recommended use of meningococcal vaccines. CCDR 2001;27(ACS-6):2-36.

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