Staff screening protocols
We previously described protocols for staff screening, sample
collection, laboratory processing and results reporting in
detail.1 These methods remained unchanged throughout
this study period. Two parallel streams of entry into the testing
programme included (i) HCW symptomatic, and HCW symptomatic
household contact screening arms and (ii) an HCW asymptomatic
screening arm . In the former, any patient-facing or non-patient-facing
HCW could voluntarily refer themselves or a household contact, should
they develop symptoms suggestive of COVID-19. In the latter, HCWs could
volunteer to take part in a rolling programme of testing for all
patient-facing and non-patient-facing staff working in defined clinical
areas thought to be at risk of SARS-CoV-2 transmission. Testing was
performed (i) at temporary on-site ‘Pods’; (ii) via self-swabbing kits
delivered to HCWs in their area of work. All individuals in each arm of
the programme performed a self-swab at the back of the throat then the
nasal cavity, followed by RNA extraction and amplification using
real-time RT-PCR.11 Cluster investigation was
initiated when three or more HCWs working in the same clinical area
tested positive for SARS-CoV-2 in a one week period.