UK and US officials warn that patients receiving cochlear implants - electrodes inserted into the inner ear to restore a degree of hearing in those with severe sensorineural deafness - are at risk of contracting meningitis.
Warnings were issued after 25 cases of meningitis, nine of them fatal, were reported in implanted patients, aged 21 months to 63 years, with an onset of symptoms from 24 hours to five years after cochlear implantation.
The US FDA suspects that the true incidence is higher and that other cases have gone unreported.
Authorities are advising patients to either be vaccinated against meningitis before surgery or take prophylactic (just-in-case) antibiotics during the operation. Neither measure is 100 per cent effective (BMJ, 2002; 325: 298).