Univariate analysis for risk factors associated with seropositivity for antibodies to H9 virus amongst duck-related workers, Beijing, China.

NOTE. Data are frequency (%) of subjects, unless otherwise indicated. Univariate unconditional logistic regression was employed to compare frequencies of exposure between seropositive group and seronegative group. OR, odd ratio; CI, confidence interval; NA, not available. Boldface indicates P*Fisher’s exact test was used because data distribution could not be analyzed by logistic regression.