Table 7 Characteristics of patients included in the primary analysis by vaccination status

Number of patients, n (%)

Controls

4872

75.5

1556

77.7

0.042

Cases

1581

24.5

446

22.3

Age (y)

Median (range)

<0.001

Age group, n (%)

6–11 mo

496

7.7

3

0.1

1–4 y

2120

32.9

49

2.4

5–17 y

712

11.0

102

5.1

18–49 y

1347

20.9

75

3.7

50–64 y

591

9.2

138

6.9

65–74 y

388

6.0

416

20.8

75–84 y

512

7.9

704

35.2

≥85 y

287

4.4

515

25.7

Female, n (%)

-

2825

43.8

843

42.1

0.188

Comorbidities, n (%)

None

4505

70

366

18.3

<0.001

1

1077

16.7

647

32.3

>1

871

13.5

989

49.4

Pregnant, n (%)

-

294

4.6

3

0.1

<0.001

Obesity, n (%)

-

982

15.2

564

28.2

<0.001

Morbid obesity, n (%)

-

86

1.3

54

2.7

<0.001

Previous hospitalisation within 12 months, n (%)

-

1887

29.2

761

38

<0.001

GP visit within 3 months, n (%)

None

1815

28.1

343

17.1

<0.001

1

2027

31.4

389

19.4

>1

2606

40.4

1272

63.5

Smoking, n (%)

Current

1527

23.7

225

11.2

<0.001

Past

1069

16.6

742

37.1

Never

3856

59.8

1035

51.7

Functional impairment in ≥65 y, n (%)

None or minimal

619

54.2

1021

62.4

<0.001

Mild

324

28.4

330

20.2

Moderate

95

8.3

88

5.4

Severe

32

2.8

62

3.8

Total

72

6.3

123

7.5

Sampling interval (days)

Median (range)

<0.001

Sampling interval, n (%)

≤4 d

3703

57.4

990

49.5

<0.001

5-7 d

2587

40.1

936

46.8

8-9 d

163

2.5

76

3.8

Site, n (%)

St. Petersburg

2138

33.1

59

2.9

<0.001

Moscow

1306

20.2

39

1.9

Turkey

503

7.8

26

1.3

Beijing

996

15.4

127

6.3

Valencia

1510

23.4

1751

87.5

In 2012–2013

473

7.5

1471

73.3

<0.001

In 2013–2014

513

8.1

1722

87.1

<0.001