Table 1 Baseline characteristics of individuals hospitalized at Kaiser Permanente Southern California from 3/1/2020 to 5/31/2022^a

Age

 18–< 35 years

28,774 (16.3)

1,764 (7.9)

694 (5.4)

 36–< 50 years

23,492 (13.3)

4,156 (18.5)

904 (7.1)

 50–< 65 years

40,124 (22.7)

7,732 (34.5)

2,459 (19.2)

 65–< 75 years

37,208 (21.0)

4,577 (20.4)

3,113 (24.3)

 ≥ 75 years

47,190 (26.7)

4,188 (18.7)

5,625 (44.0)

Sex

 F

95,422 (54.0)

9,531 (42.5)

5,888 (46.0)

 M

81,366 (46.0)

12,886 (57.5)

6,907 (54.0)

Race/Ethnicity

 White

76,398 (43.8)

5,740 (26.1)

6,259 (49.5)

 Asian

14,514 (8.3)

1,976 (9.0)

1,064 (8.4)

 Black

19,408 (11.1)

2,076 (9.4)

1,515 (12.0)

 Hispanic

61,063 (35.0)

11,840 (53.9)

3,666 (29.0)

 Other/Unknown

2,871 (1.6)

339 (1.5)

137 (1.1)

 Unknown

2,534

446

154

Number of outpatient encounters

 0–5

36,869 (20.9)

8,430 (37.6)

2,901 (22.7)

 6–10

28,715 (16.2)

5,210 (23.2)

2,233 (17.5)

 ≥ 11

111,204 (62.9)

8,777 (39.2)

7,661 (59.9)

Number of ED encounters^b

 0

99,304 (56.2)

13,541 (60.4)

6,505 (50.8)

 1

42,636 (24.1)

5,820 (26.0)

3,197 (25.0)

 ≥ 2

34,848 (19.7)

3,056 (13.6)

3,093 (24.2)

Number of inpatient encounters^b

 0

161,562 (91.4)

21,659 (96.6)

11,037 (86.3)

 1

10,729 (6.1)

619 (2.8)

1,130 (8.8)

 ≥ 2

4,497 (2.5)

139 (0.6)

628 (4.9)

Elixhauser^b

 0–2

85,622 (48.4)

13,674 (61.0)

3,962 (31.0)

 3–5

55,755 (31.5)

6,075 (27.1)

4,240 (33.1)

 6–8

25,762 (14.6)

2,076 (9.3)

3,056 (23.9)

 ≥ 9

9,649 (5.5)

592 (2.6)

1,537 (12.0)

Previous LRTI

10,877 (6.2)

3,830 (17.1)

2,661 (20.8)

Frailty index category

 < 5

103,644 (58.6)

16,348 (72.9)

5,798 (45.3)

 5–< 15

56,350 (31.9)

5,003 (22.3)

4,700 (36.7)

 ≥ 15

16,794 (9.5)

1,066 (4.8)

2,297 (18.0)

ACIP risk category

 Low

77,424 (43.8)

10,557 (47.1)

3,385 (26.5)

 Medium

65,056 (36.8)

8,242 (36.8)

5,325 (41.6)

 High

34,308 (19.4)

3,618 (16.1)

4,085 (31.9)

ICU during index hospitalization

14,028 (7.9)

2,314 (10.3)

1,319 (10.3)

Ventilation during index hospitalization

3,470 (2.0)

1,077 (4.8)

633 (4.9)

PPSV23 receipt

 Before index-date

113,591 (64.3)

13,327 (59.5)

10,630 (83.1)

 During follow-up

3,161 (1.8)

620 (2.8)

178 (1.4)

PCV13 receipt

 Before index-date

83,521 (47.2)

8,453 (37.7)

8,837 (69.1)

 During follow-up

2,100 (1.2)

243 (1.1)

118 (0.9)

Flu vaccine

 In season prior to index date

100,043 (56.6)

11,310 (50.5)

7,928 (62.0)

 During follow-up

28,172 (15.9)

3,192 (14.2)

1,778 (13.9)

COVID-19 vaccine

 1st dose prior to index date

9,124 (5.2)

1,302 (5.8)

688 (5.4)

 1st dose during follow-up

50,001 (28.3)

11,560 (51.6)

3,052 (23.9)

 1^st and 2^nd dose prior to index date

47,578 (26.9)

1,491 (6.7)

3,133 (24.5)

 2^nd dose during follow-up

50,246 (28.4)

11,505 (51.3)

3,037 (23.7)

 1^st, 2^nd, and 3^rd dose prior to index date

25,916 (14.7)

476 (2.1)

1,880 (14.7)

 3^rd dose during follow-up

40,033 (22.6)

5,448 (24.3)

2,210 (17.3)