TABLE 1.

Prevalence and persistence of IgG and IgA antibodies, with increases and decreases in incidence, among Oulu personnel

Antibody and parametera<40 age group (n = 16)b≥40 age group (n = 24)bPc
MIF %EIA %MIF %EIA %MIFEIA
IgG prevalence54 (32/59)63 (37/59)72 (91/126)82 (102/125)0.0160.005
IgA prevalence0 (0/59)7 (4/59)26 (33/126)60 (75/125)<0.001<0.001
IgG persistence50 (8/16)63 (10/16)83 (20/24)88 (21/24)0.0370.120
IgA persistence0 (0/16)13 (2/16)17 (4/24)63 (15/24)0.1360.002
IgG + IgA0 (0/16)6 (1/16)4 (1/23)63 (15/24)1.000<0.001
IgG rise0 (0/16)0 (0/16)17 (4/24)13 (3/24)0.1360.262
IgA rise0 (0/16)6 (1/16)13 (3/24)8 (2/24)0.2621.000
IgG decrease0 (0/16)0 (0/16)29 (7/24)17 (4/24)0.0290.136
IgA decrease0 (0/16)13 (2/16)4 (1/24)29 (7/24)1.0000.272
  • a The criteria for persistence were as follows: for MIA, a titer of ≥8 in IgG and IgA antibodies for ≥3 years; for EIA, EIU values ≥30 in IgG and EIU values ≥12 in IgA antibodies for ≥3 years.

  • b n, number of subjects in group. The number of positive samples out of the total number of samples tested is given in parentheses.

  • c P values were determined by Fisher's exact test or a chi-square test.