Univariate analysis

Factor

correlation coefficient ρ

p value

Age

-0.431

0.011*

COPD

-0.422

Previous vaccination

0.149

0.402

Inhaled steroids

-0.496

0.026*

Smoking

-0.314

0.071

IL-21 at day 28

0.304

0.091

Multivariate analysis

correlation coefficient β

-0.558

0.047*

*indicates statistical significance