A Multicentric Prospective Incidence Study of Guillain-Barre Syndrome in Italy. the ITANG Study

To assess Guillain-Barre syndrome (GBS) incidence we relied on the Italian Network for the study of GBS (ITANG) established in 2010 in 7 Italian regions to analyse the association between influenza vaccination and GBS. Methods: All individuals aged 6518 years, presenting with clinical manifestations that suggested GBS according to the universally accepted Asbury's diagnostic criteria (1990) were prospectively notified to a centralised database by ITANG neurologists over the period October 1, 2010-September 30, 2011. Through a telephone survey, 9 trained interviewers followed up the cases to diagnosis and then for 1 year since hospital discharge. Validation of case reporting was performed with the support of administrative data in 5 regions. Results: We found 365 cases fulfilling the definition for GBS or one of its variants over 19,846,068 population 6518 years of age, yielding an annual incidence rate of 1.84 per 100,000 (95% CI 1.65-2.03), 2.30 (95% CI 1.99-2.60) in men and 1.41 (95% CI 1.18-1.64) in women. A highly significant peak of incidence was observed in February 2011 as compared to reference month (September 2011, rate ratio 3.3:1, p < 0.01). Conclusions: In Italy, GBS incidence was among the highest reported in Europe and higher than previously observed in Italian studies

Risk of Guillain-Barré syndrome after 2010-2011 influenza vaccination.

Influenza vaccination has been implicated in Guillain Barré Syndrome (GBS) although the evidence for this link is controversial. A case-control study was conducted between October 2010 and May 2011 in seven Italian Regions to explore the relation between influenza vaccination and GBS. The study included 176 GBS incident cases aged ≥18 years from 86 neurological centers. Controls were selected among patients admitted for acute conditions to the Emergency Department of the same hospital as cases. Each control was matched to a case by sex, age, Region and admission date. Two different analyses were conducted: a matched case-control analysis and a self-controlled case series analysis (SCCS). Case-control analysis included 140 cases matched to 308 controls. The adjusted matched odds ratio (OR) for GBS occurrence within 6 weeks after influenza vaccination was 3.8 (95 % CI: 1.3, 10.5). A much stronger association with gastrointestinal infections (OR = 23.8; 95 % CI 7.3, 77.6) and influenza-like illness or upper respiratory tract infections (OR = 11.5; 95 % CI 5.6, 23.5) was highlighted. The SCCS analysis included all 176 GBS cases. Influenza vaccination was associated with GBS, with a relative risk of 2.1 (95 % CI 1.1, 3.9). According to these results the attributable risk in adults ranges from two to five GBS cases per 1,000,000 vaccinations