Since March 10, 2020, the Newcastle upon Tyne Hospitals National Health Service (NHS)
Foundation Trust has been screening symptomatic health-care workers for severe acute
respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2). Our decision was based on
the following rationale: to maintain the health and welfare of our staff; to enable
rapid identification and isolation of infected health-care workers so as to protect
patients and the wider community, given that nosocomial transmission has been recognised
as an important amplifier in epidemics of both SARS and Middle East respiratory syndrome;
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and to enable more rapid return to work of staff during this challenging period for
the NHS. Importantly, we judged that we had sufficient capacity within our service
to absorb this additional testing.
We adapted a pathway previously implemented for community testing for SARS-CoV-2 during
the so-called containment phase of the UK response to the coronavirus disease 2019
(COVID-19) outbreak. In our model, staff (mainly hospital employees but also local
general practitioners) contact Occupational Health by email. An initial symptom screen
is done, and staff with compatible symptoms (ie, new continuous cough or fever) are
appointed to testing in a designated screening pod, staffed by trained nurses, within
24 h. Combined nose and throat swabs are taken for SARS-CoV-2 RT-PCR (RdRp assay;
Public Health England), and written advice about self-isolation is provided. The results
are conveyed within 24 h, again via email. North East Ambulance Service staff are
also tested in our Trust and were included in this analysis.
Between March 10 and 31, 2020, we did 1666 SARS-CoV-2 tests in 1654 staff. Overall,
SARS-CoV-2 was detected in 240 (14%) tests. The mean age of those testing positive
(41·7 years [SD 12·1]) or negative (40·6 years [11·5]) was similar (t test p=0·168).
12 staff were retested due to recurrent symptoms (mean interval 8 days, range 2–18).
In one of these cases, repeat testing at 14 days resulted in detection of SARS-CoV-2.
Initially, positivity rates were relatively low, at two (5%) of 38 staff tested on
March 10–11, but rose steadily throughout the testing period, to 29 (20%) of 146 staff
tested on March 30–31, the last 2 days before analysis. Inspection of the epidemic
curve suggested a period of exponential growth from March 10 until around March 24,
with a doubling time of 2·2 days (95% CI 2·0–2·4; appendix). From March 24 onwards,
the rate of increase appeared linear. Consistent with these observations, we could
fit an exponential line to the data from March 10 to March 24 (r
2=0·99), whereas data after that date conformed to a linear model (r
2=0·99). These data indicate a notable change in transmission dynamics occurring around
March 24. Social distancing measures were implemented by the UK Government on March
20 (school closures) and March 23 (widespread closures or restrictions of businesses
and transport).
To explore the occupational roles of staff that underwent testing, we cross-referenced
virological data with a prospectively maintained Occupational Health database. Although
data were incomplete, we were able to identify staff roles for 1029 staff tested,
categorising them into three groups: (1) directly patient facing (eg, nurses, doctors,
allied health professionals, porters, etc), (2) non-patient facing but potentially
at higher risk of nosocomial exposure (eg, domestic and laboratory staff), and (3)
non-clinical (eg, clerical, administrative, information technology, secretarial, etc).
As the screening criteria initially prioritised those in patient-facing roles, most
staff were in group 1 (834 [81%] of 1029), with a minority in groups 2 (86 [8%]) or
3 (109 [11%]). We hypothesised that staff in patient-facing roles would experience
a higher rate of SARS-CoV-2 infection, although comparison of positivity rates by
χ2 test yielded no evidence of a significant difference between these groups (group
1: 128 [15%] of 834; group 2: 14 [16%] of 86; group 3: 20 [18%] of 109; group 1 vs
group 2: odds ratio 1·08, 95% CI 0·59–1·97; group 1 vs group 3: 1·24, 0·74–2·09; p=0·71),
suggesting that nosocomial transmission from patients to staff was not an important
factor. This is consistent with observations in China, where staff testing was widespread.
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These data provide several important insights into the COVID-19 epidemic in England.
Given that non-clinical staff had similar positivity rates to frontline staff, we
conclude that current isolation protocols and personal protective equipment appear
sufficient to prevent high levels of nosocomial transmission to frontline staff in
our setting. Rather, the data appear to reflect wider patterns of community transmission.
Due to the national testing strategy during the analysis period, no data are available
on community spread of SARS-CoV-2 in non-hospitalised populations in England; thus,
our dataset is highly informative. We observed a shift in transmission dynamics around
March 24, concurrent with steps taken by the UK Government to implement social distancing:
schools were closed on March 20, with more widespread measures to close non-essential
shops, pubs, and restaurants and limit public transport following on March 23. Although
it is not possible to assign causality, it seems plausible that these measures have
affected community transmission of SARS-CoV-2 in our region.
Our testing protocol has enabled 1414 health-care workers to return more rapidly to
NHS service in the past 3 weeks, the vast majority returning to direct patient care.
Beyond this obvious benefit, we speculate that testing might have additional positive
effects on health behaviour, by providing health-care workers with the confidence
that they can self-isolate with mild symptoms, knowing that a rapid negative result
will enable them to return to work in a timely manner. This might lessen the desire
of staff with mild symptoms to soldier on, in fear of abandoning colleagues for 7–14
days, thereby inadvertently contributing to nosocomial transmission.
Several limitations to these data should be acknowledged. We were unable to identify
staff roles for more than a third of those tested. Furthermore, no data on symptoms
or outcomes are available. Ongoing prospective data collection will aim to capture
both of these elements in due course. The small number of non-clinical staff tested
meant that it was not possible to meaningfully compare transmission dynamics between
these groups, where more complex patterns might exist. Finally, we acknowledge possible
insensitivity of the SARS-CoV-2 RdRp assay,
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which might provide unwarranted reassurance in some cases. Nevertheless, we view this
as a risk reduction rather than elimination strategy, and continue to stress that
staff with a negative test should not return to work until their symptoms have substantially
improved. National guidance is anticipated on this issue.