Table 1 Estimation of the cumulative incidence rate ratio and the related protection fraction against excretion of SARS-CoV-2 in saliva samples of vaccinated nursing home workers with COVID-19 mRNA BNT162b2 vaccine.

Group

Week

Np

cNp [A]

Nt

cNt [B]

IR [A] / [B]

cIRR (95% CI) [C]

PF (95% CI) 1 – [C]

NV

W1

6

6

1408

1408

0.0043

-

-

W2

1

7

1254

2662

0.0026

-

-

W3

1

8

1300

3962

0.0020

-

-

1D-V

W1

1

1

658

658

0.0015

0.3566 (0.0078–2.9395)

nd

W2

1

2

1386

2044

0.0010

0.3721 (0.0377–1.9543)

nd

W3

0

2

1454

3498

0.0006

0.2832 (0.0293–1.4189)

nd

Group

Week

Np

cNp [A]

Nt

cNt [B]

IR [A] / [B]

cIRR (95% CI) [C]

PF (95% CI) 1 – [C]

NV

W1

6

6

1408

1408

0.0043

-

-

W2

1

7

1254

2662

0.0026

-

-

W3

1

8

1300

3962

0.0020

-

-

W4

2

10

1224

5186

0.0019

-

-

W5

3

13

1171

6357

0.0020

-

-

W6

3

16

1164

7521

0.0021

-

-

W7

3

19

1130

8651

0.0022

-

-

W8

1

20

1043

9694

0.0021

-

-

2D-V

W1

1

1

2348

2348

0.0004

0.0999 (0.0022–0.8238)

0.9001 (0.1762–0.9978)

W2

0

1

2379

4727

0.0002

0.0804 (0.0018–0.6262)

0.9196 (0.3738–0.9982)

W3

1

2

1988

6715

0.0003

0.1475 (0.0153–0.7391)

0.8525 (0.2609–0.9847)

W4

0

2

2149

8864

0.0002

0.1170 (0.0125–0.5491)

0.8830 (0.4509–0.9875)

W5

1

3

1868

10732

0.0003

0.1367 (0.0250–0.4974)

0.8633 (0.5026–0.9750)

W6

1

4

1711

12443

0.0003

0.1511 (0.0368–0.4684)

0.8489 (0.5316–0.9632)

W7

0

4

1322

13765

0.0003

0.1323 (0.0327–0.3981)

0.8677 (0.6019–0.9673)

W8

1

5

849

14614

0.0003

0.1658 (0.0486–0.4553)

0.8342 (0.5447–0.9514)