Two doses of pandemic influenza A(H1N1) vaccine: Tolerability in healthy young children in the Netherlands

• Published in: Human vaccines Vol. 7; no. 10; pp. 1048 - 1054
• Main Authors: Klooster, Tessa M. van 't, Kemmeren, Jeanet M., de Melker, Hester E., Vermeer-de Bondt, Patricia E., van der Maas, Nicoline A.T.
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 01.10.2011
• Subjects: Binding; Biology; Bioscience; Calcium; Cancer; Cell; Child, Preschool; Cycle; Drug-Related Side Effects and Adverse Reactions - epidemiology; Female; Humans; Immunization, Secondary - adverse effects; Immunization, Secondary - methods; Infant; Influenza A Virus, H1N1 Subtype - immunology; Influenza Vaccines - administration & dosage; Influenza Vaccines - adverse effects; Influenza Vaccines - immunology; Influenza, Human - immunology; Influenza, Human - prevention & control; Landes; Male; Netherlands; Organogenesis; Proteins; Surveys and Questionnaires; Vaccination - adverse effects; Vaccination - methods; Netherlands
• ISSN: 1554-8600; 2164-5515; 1554-8619; 2164-554X
• DOI: 10.4161/hv.7.10.16692

During the 2009 influenza pandemic, children aged 6 months up to and including 4 years, without chronic illness, were vaccinated with two doses of Pandemrix® through mass vaccination in the Netherlands. During the vaccination campaign a warning was issued about fever after the second dose of Pandemrix®. Therefore, we investigated the tolerability of both doses Pandemrix® in these children. Among parents of children eligible for vaccination, 1500 questionnaires were distributed during both, the first and second mass vaccination session. We asked for the occurrence, time interval, and duration of local reactions and systemic adverse events (AEs). The responses were 36.7% and 29.5% after each dose, respectively. Local reactions were reported in 40.4% and 39.3%, most frequently, pain at the injection site. After the first and second dose, 29.6% and 30.7% of all children experienced fever (mean temperature 38.8{degree sign}C). Other systemic AEs were reported in 41.6% and 42.9% of the children. No differences were seen between the first and second dose for all reported AEs except for pallor. One child was hospitalized after the first dose, but a causal relation to the vaccination was considered improbable. In conclusion, fever was frequently reported in children 6 months up to and including 4 years of age after the first and second dose of Pandemrix®. However, for almost all AEs, including fever, no dose effect was observed. Reported AEs were mostly mild and all were transient.