Table 3.

Antibody titers (mean ± SEM) and clinical symptoms (mean ± SD) differing according to age groups

Antibody response (OD@450 nm)	Age 1 (≤36)	Age 2 (37–46)	Age 3 (47–57)
First antibody response (15 days PSO)	1.3a ± 0.08	1.4ab ± 0.16	1.7b ± 0.17
Second antibody response (30 days PSO)	1.3 ± 0.09	1.5 ± 0.13	1.6 ± 0.13
Third antibody response (45 days PSO)	1.2a ± 0.08	1.4ab ± 0.14	1.6b ± 0.12
Fourth antibody response (60 days PSO)	1.3a ± 0.07	1.5ab ± 0.14	1.6b ± 0.10
Mean of antibody response	1.3a ± 0.07	1.4ab ± 0.13	1.6b ± 0.12
Clinical symptoms duration (days)
Fever*	1.5a ± 0.58	3.9b ± 1.12	3.4b ± 0.65

Note: Groups with different letters are statistically different from each other (p < 0.05).

Abbreviation: OD, optical density; PSO, postsymptom onset.

^*Significance values have been adjusted by the Bonferroni correction for multiple tests.