ABSTRACT
Title
Active surveillance on severe drugs and vaccine events in children through a multicenter study. Safety and effectiveness of the 2009-2010 pandemic vaccine.
Authors
F. Menniti-Ippolito*, G. Traversa*, R. Da Cas* and the Italian multicenter study group for drug and vaccine safety in children
* National Center for Epidemiology, Istituto Superiore di Sanità,
Viale Regina Elena, 299
Rome
* National Center for Epidemiology, Istituto Superiore di Sanità,
Viale Regina Elena, 299
Rome
Abstract
Since 1999 an active surveillance on the role of drugs and vaccines in the occurrence of specific clinical conditions responsible for the hospitalisation of paediatric patients has been conducted in Italy. The surveillance provided useful contributions in pointing out or confirming risk signals associated with drugs and vaccines use in children. During the pandemic season 2009-2010, when the vaccination campaign was launched by the Italian Ministry of Health, the study protocol of the surveillance was adapted to include the evaluation of the safety and efficacy of the A-H1N1 vaccine. The study included children hospitalized in eight of the largest Italian paediatric hospitals or departments and was part of the Italian national pharmacovigilance plan set up to deal with the influenza pandemic.
Specifically, we aimed at verifying whether the vaccination against the A-H1N1 virus in the paediatric population: 1) increased the risk of AESI (Adverse Events of Special Interest); and 2) had a protective effect against the occurrence of ILI (Influenza Like Illness).
A case control analysis was performed in asurveillance of children hospitalized through the Emergency Departmentsof eight paediatric hospitals/wardsfor: ILI; neurological disorders; non-infectious muco-cutaneous diseases and vasculitis; thrombocytopenia; and gastroduodenal lesions.
Among 492 children enrolled from November 2009 to August 2010, only 25 were vaccinated with the pandemic vaccine. Out of 281 children admitted for a diagnosis compatible with AESI, 6 had received the A-H1N1 vaccine, though none occurred within the predefined risk windows. Only 35 children performed the laboratory test: 11 resulted positive and 24 negative for the A-H1N1 virus. Since none of the children who were A-H1N1 positive had received the pandemic vaccine it was not possible to estimate the effectiveness.
The study provides further evidence of a positive benefit-risk profile of the pandemic vaccine. No sign of risk associated with the anti A-H1N1 vaccine used in Italy was pointed out.Several limitations were observed: in Italy, the pandemic vaccination coverage was low; the epidemic was almost over by mid December 2009; and the A-H1N1 laboratory test was performed only during the epidemic phase (in less than 10% of children).
The main strength was represented by the promptness to adapt the activities of an existing network of hospitals for the evaluation of signals relevant to new vaccines.
Specifically, we aimed at verifying whether the vaccination against the A-H1N1 virus in the paediatric population: 1) increased the risk of AESI (Adverse Events of Special Interest); and 2) had a protective effect against the occurrence of ILI (Influenza Like Illness).
A case control analysis was performed in asurveillance of children hospitalized through the Emergency Departmentsof eight paediatric hospitals/wardsfor: ILI; neurological disorders; non-infectious muco-cutaneous diseases and vasculitis; thrombocytopenia; and gastroduodenal lesions.
Among 492 children enrolled from November 2009 to August 2010, only 25 were vaccinated with the pandemic vaccine. Out of 281 children admitted for a diagnosis compatible with AESI, 6 had received the A-H1N1 vaccine, though none occurred within the predefined risk windows. Only 35 children performed the laboratory test: 11 resulted positive and 24 negative for the A-H1N1 virus. Since none of the children who were A-H1N1 positive had received the pandemic vaccine it was not possible to estimate the effectiveness.
The study provides further evidence of a positive benefit-risk profile of the pandemic vaccine. No sign of risk associated with the anti A-H1N1 vaccine used in Italy was pointed out.Several limitations were observed: in Italy, the pandemic vaccination coverage was low; the epidemic was almost over by mid December 2009; and the A-H1N1 laboratory test was performed only during the epidemic phase (in less than 10% of children).
The main strength was represented by the promptness to adapt the activities of an existing network of hospitals for the evaluation of signals relevant to new vaccines.
- Menniti-Ippolito F, Sagliocca L, Da Cas R, et al. Niflumic acid and cutaneous reactions in children. Arch Dis Child 2001;84:430-1.
- Menniti-Ippolito F, Traversa G, Da Cas R, et al. Extrapyramidal reactions in children treated with metoclopramide. Ital J Pediatr 2004;30:49-52.
- Bertuola F, Morando C, Menniti-Ippolito F, et al. Association between drug and vaccine use and acute immune thrombocytopenia in childhood. A case control study in Italy. Drug Safety 2010;33:65-72.
- Italian Ministry of Health. National Plan for preparedness and response to an influenza pandemic. Rome: Ministry of Health. 2006. Available from: http://www.salute.gov.it/imgs/C_17_pubblicazioni_511_allegato.pdf