Guillain-Barré syndrome: Background incidence rates in the Netherlands
Guillain-Barré syndrome (GBS) is a (sub)acute polyradiculoneuropathy, which may occur following immunization. To interpret the occurrence of GBS after introduction of large-scale immunization programmes, it is important to define recent background incidence rates (IRs) of GBS. We used a general practitioner electronic medical record database to assess age-specific GBS IRs between 1996 and 2008 in The Netherlands. All possible GBS cases were manually reviewed. Validated incident cases were reviewed by a neurologist (B. J.) for diagnostic certainty using the GBS case definition of the Brighton Collaboration (BC). In a population of 638,891 persons, we identified 23 validated incident GBS cases (mean age 46 years). IR was 1.14 per 100,000 person years (95% confidence interval [CI] 0.67-1.61) and was lower for people under 50 years (0.76; 95%CI 0.41-1.32) compared with elderly of 50 years or older (1.80; 95%CI 0.98-3.05). Only six cases fulfilled level 1 or 2 of diagnostic certainty of the BC case definition. IR of GBS increases with age. As vaccinations are often targeted at specific age groups, age-specific rates should be used to monitor GBS observed versus expected rates after introduction of large-scale vaccination programmes.