Table.

Definitions of health-care associated COVID-19

	Label	Definition	Total (n)
1	Community onset, community associated	Diagnostic sample positive within 48 h of admission and no health-care contact during the previous 14 days	263
2	Community onset, suspected health-care associated	Diagnostic sample positive within 48 h of admission with health-care contact during the previous 14 days	32
3	Hospital onset, indeterminate health-care associated	Diagnostic sample positive after 48 h but less than 7 days post-admission	13
4	Hospital onset, suspected health-care associated	Diagnostic sample positive 7–14 days post-admission	14
5	Hospital onset, health-care associated	Diagnostic sample positive more than 14 days post-admission	43
6	Health-care worker	Any positive test identified as coming from a health-care worker*	9

Different categories of hospital onset infection reflect the increasing likelihood of hospital acquired infection based on the incubation period of the virus. N=374 is the number of CUH patients included in the study period, of whom 262 (70%) had sequencing available for analysis (appendix p 9). CUH=Cambridge University Hospitals National Health Service Foundation Trust.

^*These data do not include 37 health-care workers identified through the CUH screening programme.