[Pharmacovigilance study of influenza A H1N1 vaccination during the 2009-2010 season in France]

Abstract

We analyzed safety data on A (H1N1) v vaccines collected by the French Network of Pharmacovigilance centers from 21 October 2009 to 15 June 2010, and reported online by both practitioners and patients. During the campaign, 4.1 millions doses of Pandemrix and 1.6 million doses of Panenza were administered. With Pandemrix, 4183 AEs were reported, including 193 "serious" events. With Panenza, 566 AEs were reported, including 70 "serious" events. The most frequently reported serious AEs were neurological disorders, both with Pandemrix (38.9%, mainly isolated ascending paresthesia, with no other neurological symptoms or complications) and with Panenza (39.9%). Febrile seizures were the most frequent neurological AEs in children vaccinated with Panenza. All reported deaths (n = 22) were attributed to causes other than recent A (H1N1) v vaccination. No causal relationship was established between the AEs and vaccination. Among AEs of particular interest, 13 cases of confirmed Guillain Barre syndrome and 15 cases of demyelinating disorders were notified. No reports of narcolepsy were received during the study period. This study shows that neurological AEs (isolated ascending paresthesia with Pandemrix and febrile seizures with Panenza) are among the most frequently reported serious AEs with both vaccines. Despite the limits of this survey, based on spontaneous reports, no alert signals were noted during 8 months of follow-up. The safety profile of A (H1N1) v vaccines appears similar to that of seasonal influenza vaccines.