Skip to main content

Table 2 Mean number of contacts stratified by study wave

From: Longitudinal social contacts among school-aged children during the COVID-19 pandemic: the Bay Area Contacts among Kids (BACK) study

 

Wave 1 (May 2020)

Wave 2 (September 2020)

Wave 3 (February 2021)

 

N = 1417

827 children, 612 households

N = 1689

982 children, 716 households

N = 1446

865 children, 639 households

 

Mean (95% CI)

Observations

Mean (95% CI)

Observations

Mean (95% CI)

Observations

All contacts

2.28 (1.99, 2.58)

1417

3.24 (2.93, 3.58)

1689

3.31 (3.02, 3.62)

1446

Age

 0-4

1.83 (1.26, 2.48)

135

2.39 (1.79, 3.1)

161

2.29 (1.82, 2.85)

183

 5–12

1.03 (0.77, 1.32)

445

2.53 (2.13, 2.98)

498

2.73 (2.31, 3.22)

432

 13–17

0.77 (0.53, 1.09)

236

2.1 (1.7, 2.59)

287

2.63 (2.04, 3.33)

215

 18–39

4.27 (3.43, 5.18)

265

4.49 (3.82, 5.21)

336

4.22 (3.62, 4.88)

352

 40–64

3.59 (2.9, 4.35)

328

4.23 (3.67, 4.83)

403

4.25 (3.59, 5.01)

262

 65+

2.9 (0.4, 6)

8

1.5 (0, 6)

4

4.5 (3, 6)

2

Race

 White alone

2.25 (1.88, 2.65)

799

3.47 (3.07, 3.91)

986

3.64 (3.22, 4.09)

778

 Asian alone

2.05 (1.51, 2.66)

366

2.36 (1.96, 2.83)

391

2.55 (2.11, 3.02)

405

 Black or African American alone

2.28 (1.54, 3.14)

116

3.86 (2.48, 5.62)

103

4.1 (2.85, 5.57)

110

 Two or More Races

3.8 (1.83, 6.2)

69

4.92 (2.73, 7.8)

91

3.17 (1.74, 5.39)

58

 Some other race alone

1.85 (0.98, 2.98)

56

2.09 (1.27, 3.08)

104

3.09 (1.96, 4.49)

80

 American Indian or Alaska Native alone

2.89 (0, 21)

8

4.17 (1, 10)

6

2.29 (1, 3.67)

13

 Native Hawaiian or Pacific Islander alone

4 (1, 10)

3

2.12 (1, 3.25)

8

1 (1,1)

2

Hispanic

 Hispanic household

3.33 (2.49, 4.29)

261

3.55 (2.73, 4.56)

321

3.66 (3, 4.42)

312

 Non-Hispanic household

2.04 (1.74, 2.34)

1156

3.16 (2.83, 3.52)

1368

3.21 (2.89, 3.56)

1134

Household size

 2

2.84 (1.8, 4.08)

98

4.05 (2.54, 5.88)

123

5.14 (3.83, 6.54)

153

 3

3 (2.44, 3.63)

410

2.46 (2.06, 2.93)

443

2.89 (2.39, 3.46)

376

 4

1.81 (1.43, 2.24)

618

3.38 (2.94, 3.86)

713

2.91 (2.49, 3.36)

572

 5 or more

2.04 (1.43, 2.75)

291

3.51 (2.69, 4.55)

410

3.47 (2.89, 4.11)

345

Household income

 Less than $19,999

4.23 (2.76, 6.05)

63

3.3 (2.02, 5.14)

84

3.68 (2.5, 4.98)

85

 $20,000 to $39,999

2.65 (1.66, 3.92)

106

3.82 (2.63, 5.3)

123

3.86 (2.68, 5.34)

122

 $40,000 to $59,999

2.6 (1.54, 3.95)

110

3.35 (2.41, 4.51)

164

3.04 (2.21, 4.06)

140

 $60,000 to $79,999

3.23 (2.12, 4.59)

132

2.52 (1.86, 3.33)

173

3.25 (2.29, 4.44)

160

 $80,000 to $99,999

2.66 (1.63, 3.85)

133

3.6 (2.35, 5.3)

172

2.76 (2.08, 3.64)

172

 $100,000 to $149,999

2.59 (1.87, 3.39)

265

3.43 (2.78, 4.19)

342

3.58 (2.98, 4.24)

328

 $150,000 or more

1.5 (1.2, 1.85)

608

3.03 (2.58, 3.54)

631

3.18 (2.7, 3.69)

439

County

 San Francisco

4.81 (3.57, 6.23)

143

4.05 (3.2, 5.02)

337

3.45 (2.87, 4.08)

379

 Marin

3.62 (0, 9.67)

9

2.65 (0.72, 6.05)

24

2.69 (0.7, 6.5)

15

 Solano

2.89 (1.24, 5.08)

50

3.5 (2.3, 4.79)

76

2.72 (1.7, 3.71)

28

 Sonoma

2.84 (1.27, 5)

51

3.08 (2.11, 4.13)

93

3.19 (2, 4.52)

72

 San Mateo

2.81 (1.67, 4.21)

98

2.42 (1.78, 3.15)

162

2.36 (1.66, 3.15)

105

 Napa

2.1 (0.57, 5.33)

14

1.5 (1, 2)

6

4.85 (1.22, 10.5)

16

 Santa Clara

1.88 (1.3, 2.56)

233

3 (2.48, 3.61)

397

3.21 (2.61, 3.89)

288

 Alameda

1.8 (1.43, 2.23)

516

2.99 (2.39, 3.67)

396

3.52 (2.85, 4.29)

325

 Contra Costa

1.74 (1.23, 2.36)

303

3.47 (2.41, 4.94)

198

3.33 (2.62, 4.1)

218

Adults working from home1

 Same or less

3.67 (2.92, 4.48)

325

3.38 (2.94, 3.87)

819

3.51 (3.09, 3.96)

767

More adults working from home

1.79 (1.51, 2.09)

1037

2.96 (2.54, 3.45)

803

3.02 (2.59, 3.49)

627

Vaccination status1

 0 household members vaccinated

–

–

–

–

2.64 (2.32, 2.97)

868

≥1 household member vaccinated

–

–

–

–

4.32 (3.78, 4.89)

577

  1. We took 10,000 bootstrapped estimates from each wave of BACK, clustering at the household level, and computed bootstrapped mean estimates within each strata. We summarized the point estimate and 95% CI as the 2.5 and 97.5% quantiles of the distribution of bootstrapped estimates
  2. 1Does not sum to the number of individuals since this was not a required question
Back to article page

BMC Infectious Diseases

ISSN: 1471-2334

Contact us