Effectiveness of seasonal 2012/13 vaccine in preventing laboratory-confirmed influenza infection in primary care in the United Kingdom: mid-season analysis 2012/13

Influenza vaccine effectiveness estimates in Europe in a season with three influenza type/subtypes circulating: the I-MOVE multicentre case–control study, influenza season 2012/13

“…The I-MOVE multicentre case-control study provided adjusted type/subtype-specific VE estimate early in this season, as did other studies [7,12,13,[26][27][28][29]. The information was shared with WHO in time for the 2013/14 influenza vaccine composition meeting in February 2013.…”

A 2013/2014 northern hemisphere season surface antigen inactivated trivalent influenza vaccine - Assessing the immunogenicity and safety in an open label, uncontrolled study

“…12 Only for the A(H1N1) strain, twice as many elderly subjects compared to adult subjects reached pre-vaccination SRHs areas 25 mm. 2 Furthermore, it is noteworthy that highest pre-vaccination protection was present for the B strain in both age groups. Although the current strain (B/Massachusetts/2/2012) had not been part of the seasonal influenza vaccine the year before, the 2011/12 vaccine already included a strain from the Yamagata lineage (B/Wisconsin/1/2010) as strains from the Victoria lineage stopped being most prominent in 2011 after several years.…”

“…Serum antibody titers against the 3 antigens were measured by single radial hemolysis (SRH) assay as described elsewhere 12 as well as by hemagglutination inhibition (HI) assays using WHO antigens 15 for confirmatory purposes. For the SRH assay, seroprotection was defined as SRH area 25 mm 2 , seroconversion was defined as (i) day 1 SRH area with a negative result and day 22 SRH area 25 mm 2 or day 1 SRH area >4 mm 2 and an increase of at least 50% of the SRH area at day 22. For the HI assay, seroprotection was defined as titer 1:40, seroconversion or significant increase was defined as (i) day 1 HI titer <1:10 and day 22 HI titer 1:40 or (ii) day 1 titer 1: 10 and a 4-fold increase in HI titer on day 22.…”

“…[1][2][3] Due to antigen drift virus strains vary from one year to another. 4 This necessitates extensive surveillance of the circulating strains to match the most prevalent strains with the subsequent seasonal vaccine composition.…”

Effectiveness of 2012–2013 influenza vaccine against influenza-like illness in general population

“…Overall in Europe, throughout the 2012-2013 season, 99% of both the A(H1N1)pdm09 and A(H3N2) viruses showed a good match with the seasonal vaccine. 12 In France, among influenza B viruses for which the determination of lineage was performed, 92% belonging to B-Yamagata lineage and were similar to the vaccine strain "B/ Wisconsin/1/2010" of the season influenza vaccine 2012-2013. 13 Similarly to our results, early estimates of IVE measured through a test-negative case-control study in five European Union countries (week 43/2012-week 3/2013), showed a moderate VE against all influenza viruses (VE = 62.2%; 21.1 to 81.9).…”