Table 4 Results of Poisson regression of hospitalization rate and loglinear regression of recovery time after infection

Last dose of vaccine over 6 months ago (reference)

Emergency fourth-dose vaccination within 1 month

0.114**

-0.128***

Last dose of vaccine 1 to 6 months ago

0.499

-0.032

Female (reference)

Male

0.540

-0.201***

< 30 years old (reference)

31–40 years old

0.707

0.151***

41–50 years old

0.941

0.207***

51–60 years old

0.000***

0.252***

No underlying disease (reference)

Endocrine system

1.321

0.064

Respiratory system

0.000***

0.227

Circulatory system

3.306

0.027

Other system

4.037**

0.106*