Table 1. Characteristics of COVID-19 households and household contacts, United Kingdom, January to March 2020 (n = 472 contacts).
| Non-casesa | Probable secondary cases | Confirmed SARS-CoV-2 | All | |||||
|---|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | n | % | |
| Total | 311 | 96 | 65 | 472 | ||||
| Lost to follow-up | ||||||||
| Yes | 24 | 7.7 | 3 | 3.1 | 5 | 7.7 | 32 | 6.8 |
| No | 287 | 92.3 | 93 | 96.9 | 60 | 92.3 | 440 | 93.2 |
| Household size (number of people) | ||||||||
| 2 | 39 | 12.5 | 17 | 17.7 | 21 | 32.3 | 77 | 16.3 |
| 3 | 63 | 20.3 | 25 | 26.0 | 18 | 27.7 | 106 | 22.5 |
| 4 | 104 | 33.4 | 30 | 31.2 | 18 | 27.7 | 152 | 32.2 |
| 5 | 61 | 19.6 | 18 | 18.8 | 7 | 10.8 | 86 | 18.2 |
| 6 | 22 | 7.1 | 4 | 4.2 | 1 | 1.5 | 27 | 5.7 |
| 7 | 22 | 7.1 | 2 | 2.1 | 0 | 0.0 | 24 | 5.1 |
| Age (years) | ||||||||
| <18 | 126 | 40.5 | 33 | 34.4 | 9 | 13.8 | 168 | 35.6 |
| 18–64 | 173 | 55.6 | 63 | 65.6 | 50 | 76.9 | 286 | 60.6 |
| ≥ 65 | 12 | 3.9 | 0 | 0.0 | 6 | 9.2 | 18 | 3.8 |
| Sex | ||||||||
| Female | 161 | 51.8 | 46 | 47.9 | 34 | 52.3 | 241 | 51.1 |
| Male | 150 | 48.2 | 50 | 52.1 | 31 | 47.7 | 231 | 48.9 |
| Comorbidities | ||||||||
| Any comorbidityb | 30 | 9.6 | 13 | 13.5 | 17 | 26.2 | 60 | 12.7 |
| Asthma requiring medication | 13 | 4.2 | 2 | 2.1 | 10 | 15.4 | 25 | 5.3 |
| Respiratory disease excluding asthma | 5 | 1.6 | 3 | 3.1 | 2 | 3.1 | 10 | 2.1 |
| Diabetes | 4 | 1.3 | 2 | 2.1 | 1 | 1.5 | 7 | 1.5 |
| Heart disease | 5 | 1.6 | 1 | 1.0 | 1 | 1.5 | 7 | 1.5 |
| Immunodeficiency | 4 | 1.3 | 1 | 1.0 | 1 | 1.5 | 6 | 1.3 |
| Malignancy | 0 | 0.0 | 3 | 3.1 | 2 | 3.1 | 5 | 1.1 |
| Neurological disease | 2 | 0.6 | 1 | 1.0 | 2 | 3.1 | 5 | 1.1 |
| Kidney disease | 2 | 0.6 | 1 | 1.0 | 1 | 1.5 | 4 | 0.8 |
| No comorbidity | 252 | 81.0 | 80 | 83.3 | 45 | 69.2 | 377 | 79.9 |
| Unknown | 29 | 9.3 | 3 | 3.1 | 3 | 4.6 | 35 | 7.4 |
COVID-19: coronavirus disease.
a Non-cases include household contacts with no respiratory symptoms, contacts who developed respiratory symptoms > 14 days after symptom onset in the primary case, and contacts with unrelated prior illnesses (identified through review of household symptomology dates and HPZone case notes).
b Seven household contacts had multimorbidity, therefore the total of the number of contacts with each individual comorbidity will sum to more than the total number of contacts with ‘Any comorbidity’.