Table 1.
Summary of study cohort.
| Wave 1 | Wave 2 | |
|---|---|---|
| Dates | 1st March 2020 to 25th July 2020 | 30th November 2020 to 24th January 2021 |
| Total Cases | 1302 | 879 |
| Patients | 780 (59.9%) | 580 (66.0%) |
| Staff | 522 (40.1%) | 299 (34.0%) |
| Number of hospital locations | 120 | 93 |
| Global PANGO lineages | 64 | 24 |
| Fraction of patients with inferred symptom onset date | 30.1% | 22.0% |
| Median ward movements per patient (min-max) | 2 (1–9) | 2 (1–9) |
| Patient classification | ||
| Community onset—community associated | 486 (62.3%*) | 236 (40.7%*) |
| Community onset—suspected healthcare associated | 79 (10.1%*) | 67 (11.6%*) |
| Hospital onset—healthcare associated | 80 (10.3%*) | 100 (17.2%*) |
| Hospital onset—probable healthcare associated | 74 (9.5%*) | 88 (15.2%*) |
| Hospital onset—intermediate healthcare associated | 61 (7.8%*) | 89 (15.3%*) |
Number of hospital locations includes wards and non-clinical areas. Ward movements refer to between ward movements and do not include bed movements within the same ward. Classification of patient cases according to likely source of infection (community or hospital-acquired) is based on SAGE criteria15. Community onset-community associated = positive test up to 14 days before or within 2 days after hospital admission; Community onset-suspected healthcare associated = positive test up to 14 days before or within 2 days after admission, with discharge from hospital within 14 days before test; Hospital onset-intermediate healthcare associated = positive test 3–7 days after hospital admission with no discharge from hospital in 14 days before the specimen date; Hospital onset-suspected healthcare associated = positive test 8–14 days after admission or 3–14 days after admission with discharge from hospital in 14 days before test; Hospital onset-healthcare associated = positive test 15 or more days after hospital admission. Asterix represents percentage of patient cases.