Research Article: Estimates of Pandemic Influenza Vaccine Effectiveness in Europe, 2009–2010: Results of Influenza Monitoring Vaccine Effectiveness in Europe (I-MOVE) Multicentre Case-Control Study

Date Published: January 11, 2011

Publisher: Public Library of Science

Author(s): Marta Valenciano, Esther Kissling, Jean-Marie Cohen, Beatrix Oroszi, Anne-Sophie Barret, Caterina Rizzo, Baltazar Nunes, Daniela Pitigoi, Amparro Larrauri Cámara, Anne Mosnier, Judith K. Horvath, Joan O’Donnell, Antonino Bella, Raquel Guiomar, Emilia Lupulescu, Camelia Savulescu, Bruno C. Ciancio, Piotr Kramarz, Alain Moren, Lone Simonsen

Abstract: Results from a European multicentre case-control study reported by Marta Valenciano and colleagues suggest good protection by the pandemic monovalent H1N1 vaccine against pH1N1 and no effect of the 2009–2010 seasonal influenza vaccine on H1N1.

Partial Text: Following the World Health Organization’s declaration of pandemic phase six in June 2009, manufacturers developed vaccines against pandemic influenza A (H1N1) 2009 (pH1N1). On the basis of advice from the European Medicine Agency (EMA), the European Commission initially granted marketing authorization for three pandemic vaccines to be used in European Union (EU) countries. In selected countries including France, Hungary, and Romania, national regulatory authorities provided a licence for additional vaccines. Early clinical trials showed that the pandemic vaccines elicited good immunological responses after the first dose [1]–[3]. However, as strong immunogenicity does not always result in robust vaccine effectiveness (VE), it was important to estimate the effectiveness of the vaccine at the population level.

The study was conducted within the context of the existing European Influenza Surveillance Network (EISN) [12]. At the seven study sites, EISN sentinel primary care practitioners were invited to participate in the study. In Portugal and Italy, practitioners other than those participating in EISN, were also invited to participate.

In the seven participating countries, influenza activity peaks were reached between week 43 (Ireland) and week 50 (Hungary, Romania) (Figure S1) of 2009. Of the six vaccines used at the seven study sites, three were adjuvanted (Table S1). The first country to start a pandemic vaccination campaign was Hungary (week 40) and the last was Romania (week 48) (Figure S1; Table 1).

Using sentinel practitioner networks in seven EU countries, we estimated the effectiveness of the 2009–2010 pandemic and seasonal influenza vaccines. The pooled results suggest that one dose of a pandemic vaccine conferred good protection against medically attended pH1N1 ILI (65.5%–100% according to the various stratified analyses performed). The PIVE was higher in persons aged <65 y old and in those without any chronic disease. Furthermore, the PIVE point estimates suggest a good PIVE as early as 8 d after vaccination. During the study period, the 2009–2010 seasonal vaccine seems to have had no effect on pH1N1 illness. Source: http://doi.org/10.1371/journal.pmed.1000388

 

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