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Volume 26, Number 8—August 2020
Synopsis

Investigation and Serologic Follow-Up of Contacts of an Early Confirmed Case-Patient with COVID-19, Washington, USA

Victoria T. Chu1Comments to Author , Brandi Freeman-Ponder1, Scott Lindquist, Christopher Spitters, Vance Kawakami, Jonathan W. Dyal, Shauna Clark, Hollianne Bruce, Jeffrey S. Duchin, Chas DeBolt, Sara Podczervinski, Marisa D’Angeli, Kristen Pettrone, Rachael Zacks, Grace Vahey, Michelle L. Holshue, Misty Lang, Rachel M. Burke, Melissa A. Rolfes, Mariel Marlow, Claire M. Midgley, Xiaoyan Lu, Stephen Lindstrom, Aron J. Hall, Alicia M. Fry, Natalie J. Thornburg, Susan I. Gerber, Satish K. Pillai, and Holly M. Biggs
Author affiliations: Centers for Disease Control and Prevention, Atlanta, Georgia, USA (V.T. Chu, B. Freeman-Ponder, J.W. Dyal, Kristen Pettrone, R. Zacks, G. Vahey, M.L. Holshue, R.M. Burke, M.A. Rolfes, M. Marlow, C.M. Midgley, X. Lu, S. Lindstrom, A.J. Hall, A.M. Fry, N.J. Thornburg, S.I. Gerber, S.K. Pillai, H.M. Biggs); Washington State Department of Public Health, Shoreline, Washington, USA (S. Lindquist, C. DeBolt, S. Podczervinski, M. D’Angeli, M.L. Holshue, M. Lang); Snohomish Health District, Everett, Washington, USA (C. Spitters, H. Bruce); Public Health—Seattle and King County, Seattle, Washington (V. Kawakami, S. Clark, J.S. Duchin); University of Washington, Seattle (J.S. Duchin)

Main Article

Table 3

Demographic characteristics, underlying medical conditions, exposures, and SARS-CoV-2 testing among contacts of an early confirmed US COVID-19 case participating in the enhanced contact investigation, Washington, USA, 2020*

Characteristic
All contacts, N = 38
Community contacts
Healthcare contacts
Office co-workers, n = 11
Waiting room contacts, n = 20

Healthcare personnel, n = 7†
Age, y, median (range)
45 (0–78)
39 (24–62)
53.5 (<1–78)

36 (30–56)
Sex
M 21 (55) 9 (82) 9 (45) 3 (43)
F
17 (45)
2 (18)
11 (55)

4 (57)
Race
White 27 (71) 2 (18) 18 (90) 7 (100)
Asian 8 (21) 8 (73) 0 0
Black 0 0 0 0
Not specified
3 (8)
1 (9)
2 (10)

0
Ethnicity
Hispanic/Latino 5 (13) 0 3 (15) 2 (29)
Not Hispanic/Latino 28 (74) 10 (91) 14 (70) 4 (57)
Not specified
5 (13)
1 (9)
3 (15)

1 (14)
Underlying medical conditions‡
None 15 (39) 8 (73) 3 (15) 4 (57)
Asthma 10 (26) 3 (27) 4 (20) 3 (43)
Diabetes mellitus, type 2 4 (11) 0 4 (20) 0
Hypertension 7 (18) 1 (9) 6 (30) 0
Coronary artery disease 1 (3) 0 1 (5) 0
Immunosuppressive condition or therapy 1 (3) 0 1 (5) 0
Pregnant or postpartum§
2 (5)
0
1 (5)

1 (14)
Exposure type¶
Face-to-face interaction 16/18 (89) 11 (100) NA 5 (71)
Direct physical contact 10/18 (56) 6 (55) NA 4 (57)
Physically within 6 feet 16/18 (89) 11 (100) NA 5 (71)
Within 6 feet while case-patient was coughing or sneezing 3/18 (17) 0 NA 3 (43)
Touched object handled by the case-patient 13/18 (72) 10 (91) NA 3 (43)
In the same room 14/18 (78) 9 (82) NA 5 (71)
Traveled in the same vehicle
3/18 (17)
3 (28)
NA

0
Active monitoring
Days from last exposure to start of active monitoring, median (range) 4 (1–7) 6 (5–7) 4 (4–5) 1 (1–1)
Assessed as PUI during monitoring period† 7 (18) 2 (18) 4 (20) 1 (14)
Days from last exposure until symptom onset among PUIs
5 (1–11)
6 (1–11)
4.5 (3–11)

6 (6–6)
Laboratory testing
Any testing (rRT-PCR or serology)
37 (97)
11 (100)
19 (95)

7 (100)
Enhanced contact investigation: initial specimen collection within 14 d after last exposure to case-patient
Contacts with respiratory specimens# 36 (95) 11 (100) 19 (95) 6 (86)
Contacts with serum specimens 28 (74) 8 (73) 14 (75) 6 (86)
Days from last exposure to initial specimen collection (respiratory and serum specimens) among asymptomatic contacts, median (range)
11 (9–13)
10 (10–11)
11 (10–13)

9 (9–11)
Enhanced contact investigation: follow-up serum, ≈6 weeks after last exposure to case-patient
Contacts with follow-up serum specimens 23 (61) 9 (82) 10 (50) 4 (57)
Days from last exposure to follow-up serum collection, median (range) 46 (44–49) 47 (46–47) 46 (44–49) 46 (45–47)

*Values are no. persons except as indicated. COVID-19, coronavirus disease; HCP, healthcare personnel; NA, not asked; PUI, person under investigation; rRT-PCR, real-time reverse transcription PCR.
†One HCP PUI was not available for interview and was not included in this table. Nasopharyngeal and oropharyngeal specimens were collected for this PUI testing, and were negative by rRT-PCR for SARS-CoV-2. No serum specimens were collected.
‡Some contacts had >1 underlying medical condition.
§Postpartum was defined as within 6 weeks after delivery.
¶Exposure types were not asked for waiting room contacts, as the case-patient was anonymous to the waiting room contacts.
#Included respiratory specimens obtained for PUI testing.

Main Article

1These authors contributed equally to this article.

Page created: May 12, 2020
Page updated: July 17, 2020
Page reviewed: July 17, 2020
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