Table 2.
Symptoms, Secondary Attack Rates, and Relative Risks for Contacts in Households Without Co-Primary Cases
| Index Child's SARS-CoV-2 Status | All | HH Contact Age Group | ||||||
|---|---|---|---|---|---|---|---|---|
| <18 Years | 18 to <50 Years | 50+ Years | ||||||
| Positivea | Negativeb | Positive | Negative | Positive | Negative | Positive | Negative | |
| No. (% within SARS-CoV-2 status group) | 179 (50 HH) | 663 (182 HH) | 62 (34.3) | 246 (37.1) | 92 (51.4) | 346 (52.2) | 22 (12.2) | 63 (9.5) |
| Any symptoms (clinical SAR) [95% CI] | 19 (10.6)[6.5–16.1] | 13 (2.0)[1.0–3.3] | 3 (4.8)[1.0–13.5] | 1 (0.4)[0–13.5] | 15 (16.1)[9.4–25.5] | 10 (2.9)[1.4–5.3] | 1 (4.5)[.1–22.8] | 2 (3.2)[0.4–11.0] |
| RR [95% CI] by HH contact age group (within SARS-CoV-2 status group) | … | … | ref | ref | 3.4 [1.0–11.2] | 7.1 [.9–55.2] | 0.9 [.1–8.6] | 7.8 [0.7–84.8] |
| RR [95% CI], SARS-CoV-2–positive vs –negative (within HH contact age group) | 5.4 [2.7–10.7] | ref | 11.9 [1.3–112.5] | ref | 5.6 [2.6–12.1] | ref | 1.4 [.1–15.0] | ref |
| Acute respiratory illnessc (%) [95% CI] | 7 (3.9)[1.6–7.9] | 7 (1.1)[.4–2.2] | 1 (1.6)[0–8.7] | 0[0–1.5] | 5 (5.4)[1.8–12.2] | 5 (1.4)[.5–3.3] | 1 (4.5)[.1–22.8] | 2 (3.2)[.4–11.0] |
| RR [95% CI] by HH contact age group (within SARS-CoV-2 status group) | … | … | ref | ref | 3.4 [0.4–28.1] | 7.1 [.9–55.2] | 2.8 [.2–43.2] | 0.5 [0–5.4] |
| RR [95% CI], SARS-CoV-2–positive vs –negative (within HH contact age group) | 3.7 [1.3–10.4] | ref | Excluded | ref | 3.8 [1.1–12.7] | ref | 1.4 [.1–15.0] | ref |
| Any known illnessd (combined SAR) [95% CI] | 25 (14.0)[9.2–19.9] | 13 (2.0)[1.0–3.3] | 6 (9.7) | 1 (0.4)[0–13.5] | 18 (19.6)[12.0–29.1] | 10 (2.9)[1.4–5.3] | 1 (4.5)[.1–22.8] | 2 (3.2)[.4–11.0] |
| RR [95% CI] by HH contact age group (within SARS-CoV-2 status group) | … | … | ref | ref | 2.0 [.9–4.8] | 7.1 [.9–55.2] | 0.5 [.1–3.7] | 7.8 [.7–84.8] |
| RR [95% CI], SARS-CoV-2–positive vs –negative (within HH contact age group) | 7.1 [3.7–13.6] | ref | 23.8 [2.9–194.1] | ref | 6.8 [3.2–14.2] | ref | 1.4 [.1–15.0] | ref |
Data are n (%) unless otherwise stated.
Abbreviations: CI, confidence interval; HH, household; ref, reference; RR, relative risk; SAR, secondary attack rate; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.
aSpecific age missing for 3 HH contacts.
bSpecific age missing for 8 HH contacts.
cAt least 2 of: fever or feverishness, cough, sore throat, runny nose.
dTest-positive and/or any symptoms.