Table 3 Cox regression results of the symptom duration after infection among nurses received emergency fourth-dose vaccination

Last dose of vaccine over 6 months ago (reference)

Emergency fourth-dose vaccination within 1 month

1.210***

1.068

0.970

1.018

1.048

1.048

1.237***

1.056

0.960

0.987

1.055

1.192**

1.331**

Last dose of vaccine 1 to 6 months ago

1.099**

1.118

1.038

0.824**

0.954

0.957

0.963

0.827

0.815*

0.924

0.956

1.072

1.116

Female (reference)

Male

0.971

1.246

1.038

0.884

0.958

0.791*

0.976

1.090

0.900

0.926

0.0991***

0.953

0.792

< 30 years old (reference)

31–40 years old

1.052

0.850**

0.921

0.928*

0.825***

0.782***

0.706***

0.942

0.859**

0.789***

0.788*

0.928

0.800***

41–50 years old

1.044

0.872

1.039

1.058

0.851**

0.910

0.553***

1.176

0.860*

0.774***

0.637**

1.093

0.678***

51–60 years old

0.936

0.903

0.972

1.032

0.839

0.732***

0.547***

1.065

1.136

0.881

0.570*

0.968

0.713

No underlying disease (reference)

Endocrine system

0.912

0.967

0.935

1.018

0.952

0.763*

0.854

0.961

1.232

0.839

1.605

0.842

0.870

Respiratory system

1.050

0.627

0.632

0.951

1.199

0.829

0.737

0.709

0.587**

1.379

0.788

0.939

1.028

Circulatory system

0.820**

0.384***

0.844

1.019

0.926

0.829

0.803

0.796

0.869

1.238

0.799

0.788

0.905

Other system

0.963

0.984

0.739

0.979

0.996

0.909

0.778

1.310

1.012

1.039

0.449

1.027

0.935