A Prospective Study of Risk Factors Associated with Seroprevalence of SARS-CoV-2 Antibodies in Healthcare Workers at a Large UK Teaching Hospital (preprint)

Background: The COVID-19 pandemic continues to grow at an unprecedented rate. Healthcare workers (HCWs) are at higher risk of SARS-CoV-2 infection than the general population but risk factors for HCW infection are not well described.Methods: We conducted a prospective sero-epidemiological study of HCWs at a UK teaching hospital using a SARS-CoV-2 immunoassay. Risk factors for seropositivity were analysed using multivariate logistic regression.Findings: 410/5,698 (7·2%) staff tested positive for SARS-CoV-2 antibodies. Seroprevalence was higher in those working in designated COVID-19 areas compared with other areas (9·47% versus 6·16%) Healthcare assistants (aOR 2·06 [95%CI 1·14-3·71]; p =0·016) and domestic and portering staff (aOR 3·45 [95% CI 1·07-11·42]; p =0·039) had significantly higher seroprevalence than other staff groups after adjusting for age, sex, ethnicity and COVID-19 working location. Staff working in acute medicine and medical sub-specialities were also at higher risk (aOR 2·07 [95% CI 1·31-3·25]; p <0·002). Staff from Black, Asian and minority ethnic (BAME) backgrounds had an aOR of 1·65 (95% CI 1·32 – 2·07; p <0·001) compared to white staff; this increased risk was independent of COVID-19 area working. The only symptoms significantly associated with seropositivity in a multivariable model were loss of sense of taste or smell, fever and myalgia; 31% of staff testing positive reported no prior symptoms.Interpretation: Risk of SARS-CoV-2 infection amongst HCWs is heterogeneous and influenced by COVID-19 working location, role, age and ethnicity. Increased risk amongst BAME staff cannot be accounted for solely by occupational factors.Funding: Wellcome Trust, Addenbrookes Charitable Trust, National Institute for Health Research, Academy of Medical Sciences, the Health Foundation and the NIHR Cambridge Biomedical Research Centre.Declaration of Interests: None to declare.Ethics Approval Statement: Ethical approval for this study was granted by the East of England – Cambridge Central Research Ethics Committee (IRAS ID: 220277).

A prospective study of risk factors associated with seroprevalence of SARS-CoV-2 antibodies in healthcare workers at a large UK teaching hospital (preprint)

Background The COVID-19 pandemic continues to grow at an unprecedented rate. Healthcare workers (HCWs) are at higher risk of SARS-CoV-2 infection than the general population but risk factors for HCW infection are not well described. Methods We conducted a prospective sero-epidemiological study of HCWs at a UK teaching hospital using a SARS-CoV-2 immunoassay. Risk factors for seropositivity were analysed using multivariate logistic regression. Findings 410/5,698 (7.2%) staff tested positive for SARS-CoV-2 antibodies. Seroprevalence was higher in those working in designated COVID-19 areas compared with other areas (9.47% versus 6.16%) Healthcare assistants (aOR 2.06 [95%CI 1.14-3.71]; p=0.016) and domestic and portering staff (aOR 3.45 [95% CI 1.07-11.42]; p=0.039) had significantly higher seroprevalence than other staff groups after adjusting for age, sex, ethnicity and COVID-19 working location. Staff working in acute medicine and medical sub-specialities were also at higher risk (aOR 2.07 [95% CI 1.31-3.25]; p=0.002). Staff from Black, Asian and minority ethnic (BAME) backgrounds had an aOR of 1.65 (95% CI 1.32-2.07; p<0.0001) compared to white staff; this increased risk was independent of COVID-19 area working. The only symptoms significantly associated with seropositivity in a multivariable model were loss of sense of taste or smell, fever and myalgia; 31% of staff testing positive reported no prior symptoms. Interpretation Risk of SARS-CoV-2 infection amongst HCWs is heterogeneous and influenced by COVID-19 working location, role, age and ethnicity. Increased risk amongst BAME staff cannot be accounted for solely by occupational factors. Funding Wellcome Trust, Addenbrookes Charitable Trust, National Institute for Health Research, Academy of Medical Sciences, the Health Foundation and the NIHR Cambridge Biomedical Research Centre.

SARS-CoV-2 antigen and antibody prevalence among UK staff working with cancer patients during the COVID-19 pandemic. (preprint)

Background International guidelines for testing potentially immunosuppressed cancer patients receiving non-surgical anticancer therapies for SARS-CoV-2 (COVID-19) are currently lacking. The value of routinely testing staff treating cancer patients is not known. Methods: Patient-facing oncology department staff at work during the COVID-19 pandemic consented to have a nasopharyngeal swab SARS-CoV-2 antigen test by polymerase chain reaction (PCR) and blood tests for SARS-CoV-2 antibody using a laboratory Luminex-based assay and a rapid point-of-care (POC) assay on 2 occasions 28 days apart in June and July 2020. Results 434 participants were recruited: nurses (58.3%), doctors (21.2%), radiographers (10.4%) and administrators (10.1%). 82% were female; median age 40-years (range 19-66). 26.3% reported prior symptoms suggestive of SARS-CoV-2 infection and 1.4% tested PCR-positive prior to June 2020. All were PCR-negative at both study day 1 and 28. 18.4% were SARS-CoV-2 sero-positive on day 1 by Luminex, of whom 42.5% also tested positive by POC. 47.5% of Luminex sero-positives had antibodies to both nucleocapsid (N) and surface (S) antigens. Nurses (21.3%) and doctors (17.4%) had higher prevalence trends of Luminex sero-positivity compared with administrators (13.6%) and radiographers (8.9%) (p=0.2). 38% of sero-positive participants reported previous symptoms suggestive of SARS-CoV-2 infection, a 1.9-fold higher odds than sero-negative participants (p=0.01). 400 participants re-tested on day 28: 13.3% were Luminex sero-positive of whom 92.5% were previously positive and 7.5% newly positive. Nurses (16.5%) had the highest seroprevalence trend amongst staff groups (p=0.07). 32.5% of day 1 sero-positives became sero-negative by day 28: the majority being previously reactive to the N-antigen only (p<0.0001). Conclusion The high prevalence of SARS-CoV-2 IgG sero-positivity in oncology nurses, and the high decline of positivity over 4 weeks supports regular antigen and antibody testing in this staff group for SARS-CoV-2 as part of routine patient care prior to availability of a vaccine.

First results from the UK COVID-19 Serology in Oncology Staff Study (CSOS) (preprint)

Background: The global SARS-CoV-2 (COVID-19) pandemic has caused substantial worldwide mortality. At present, there is no data regarding oncologist-specific SARS-CoV-2 infection/immunity rates in the United Kingdom (UK) which might impact planning for the management of potentially immunosuppressed cancer patients. Here, we present the first results from the COVID-19 Serology in Oncology Staff (CSOS) study with the aim of informing non-surgical oncology management guidelines. Methods: Patient-facing staff working in an oncology department during the COVID-19 pandemic at a large district general hospital in the East of England were invited to participate. Samples were collected during the first week of June 2020: blood for SARS-COV-2 antibody testing using a rapid lateral flow point of care (POC) assay and a laboratory Luminex based assay, as well as a nasopharyngeal swab for SARS-CoV-2 PCR testing. Participant characteristics were also collected. Results: Seventy participants were recruited: nurses (45/70; 64.3%), doctors (15/70; 21.2%), and other patient-facing staff (10/70; 14.3%). The majority were female (61/70; 87.1%) with a mean age of 42 years (median 41; range 23-64 years). A minority were smokers (9/70; 10%) or had chronic underlying health conditions (16/70; 22.9%), the commonest being asthma. All participants were nasopharyngeal-swab PCR negative, although 4/70 (5.7%) had previously tested positive by NHS testing undertaken during the preceding months. 15/70 (21.4%) had positive SARS-CoV-2 antibodies using the Luminex test. Nurses had the highest incidence of positive antibodies (13/45; 28.9%), with a lower incidence in doctors (2/15; 13.3%) although this difference was not statistically significant (Fischer's exact test p=0.3). No receptionists had positive antibody tests. All four participants with a previously reported positive PCR test were antibody-positive. 9/15 (60%) of antibody-positive participants reported previous symptoms suggestive of SARS-CoV-2 infection: a 3.6-fold higher odds than antibody-negative participants, of whom 16/55 reported symptoms (p=0.03). The mean duration of symptoms was 11 days (median 11; range 1-35 days) and the mean time from resolution of reported previous symptoms to antibody testing was 48.4 days (median 46; range 1-123 days). Conclusion: This study establishes the SARS-CoV-2 exposure and carriage rate amongst patient-facing staff working in the oncology department of a large UK general hospital during the pandemic. These results may help inform UK national oncology patient management prior to the development of a viable vaccine or treatment.