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Table 4 Strain-specific A/Salomon Islands/3/2006 (H1N1), A/Brisbane/10/2007 (H3N2) and B/Florida/4/2006 (B/Florida) hemagglutination inhibition titers, seroconversion factor, seroconversion rate, and seroprotection rate

From: Prospective surveillance study of acute respiratory infections, influenza-like illness and seasonal influenza vaccine in a cohort of juvenile idiopathic arthritis patients

 

H1N1

H3N2

B/Florida

 

Day 0

 

Day 30

Day 0

 

Day 30

Day 0

 

Day 30

Seroprotection rate a (%)

         

JIA (44)

21/43 (48.8)

 

44(100)

20/43 (46.5)

 

40(91)

20/43 (46.5)

 

42(95)

Healthy children# (10)

7(70)

 

10(100)

6(60)

 

8(80)

5(50)

 

10(100)

Seroconversion rate b (%)

         

JIA

  

40/43(93)

  

32/43 (74.4)

  

31/40 (77.5)

Healthy children

  

7/7(100)

  

3/8 (37.5)

  

6/8 (75)

Seroconversion factor c

         

JIA

  

16.5

  

5.2

  

7.2

Healthy children

  

9.8

  

3.0

  

4.0

  1. To meet the Committee for Proprietary Medicinal Products (CPMP) guidelines each of the vaccine antigens must meet at least one of the following criteria: seroprotection rate exceeding 70%, seroconversion rate exceeding 40%, and seroconversion factor exceeding 2.5. a Seroprotection rate: the percentage of vaccine recipients with a serum HI titres of at least 1:40 after vaccination. bSeroconversion rate: the percentage of vaccine recipients with an increase in serum HI titres by at least a factor of 4 after vaccination. c Seroconversion fator: the fold increase in serum geometric mean HI titres after vaccination.