Interim results 2015-16: primary care multicentre case-control study

In 2015-16, 12 study sites are participating in the primary care I-MOVE+ multicentre case-control study: Croatia, Germany, France, Hungary, Ireland, Italy, Poland, Portugal, Romania, Spain, Sweden (not funded through H2020) and the Netherlands, 

We measure  influenza VE against medically-attended laboratory confirmed influenza using a test-negative design as described in the I-MOVE+ and  I-MOVE generic protocols and in the I-MOVE multicentre case-control publications. 
 
We present below the 2015-16 interim estimates (week 41/2015 - week 3/2016) including the results in the 65+ years (target population of I-MOVE+) and in the other age groups. Romania and Croatia are not included as at the time of the analysis, there were no influenza positive cases in their studies. The 2015-16 season started late in the participating countries. Therefore, the sample size for this interim analysis was limited resulting in low precision. The results should be interpreted with caution. The final estimates will be available at the end of the influenza season. 


Table: Influenza vaccine effectiveness against medically-attended laboratory confirmed influenza by influenza type/suptype, overall and in the age group 18-64 years. I-MOVE/I-MOVE+ multicentre case control study, interim results influenza season 2015-16 (week 41/2015-week 3/2016)

Influenza
type/subtype
 Population N Cases; vaccinated Controls; vaccinated
 VE* adjusted by study site only (CI**)
 Adjusted VE* 
by study site, age, onset time

(CI**)
 Any influenza
 All ages
 1933 348; 20
 1585; 159
 65.2 (41.9-79.1)
46.3 (4.9-69.7)
  18-64 years
 1004 214; 12
 790; 57
 42.2 (-16.6-71.3)
 45.2 (-12.5-73.3)

 65+ years
 188 14; 5
 174; 88
  
  Influenza A All ages 1807 271; 18
 1536; 154
 63.7 (37.9-78.7) 44.4 (-1.1-69.5)
  18-64 years 948 173; 12
 775; 55
 34.1 (-32.8-67.3)
 36.4 (-30.6-69.0)
  65+ years 181 12; 5
 169; 85
  
 A(H1N1)pdm09 All ages 1468 246; 17
 1222; 146
 64.4 (38.4-79.5)
 44.2 (-3.1-69.8)
  18-64 years 809 158; 11 651; 54
 39.2 (-25.0-70.4)
 40.7 (-25.0-71.9)
  65+ years 157 11; 5
 146; 80
  
 Influenza B
 All ages 1015 77; 2
 938; 98
  
  65+ years 98 2; 0
 96; 55
  


* VE Vaccine effectiveness
** CI Confidence Interval
^ ISO: international Organization for Standardization
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