SARS-CoV-2 antigen and antibody prevalence among UK staff working with cancer patients during the COVID-19 pandemic
Authors: Favara David M , McAdam Karen , Cooke Anthony , Bordessa-Kelly Alex , Budriunaite Ieva , Bossingham Sophie , Houghton Sally , Doffinger Rainer , Ainsworth Nicola , Corrie Pippa G 
Published: September 2020

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.

Findings

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).

Interpretation

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.

Funding

ACT, NHS

Evidence before this study

To identify studies involving oncology healthcare workers and SARS-CoV-2 exposure during the COVID-19 pandemic, we searched PubMed and Medrxiv for articles published between January 1 and July 31 using the following search terms “COVID-19”, “SARS-CoV-2”, “oncology staff”, “healthcare workers” without language restriction. To date, no large study has specifically reported and tracked patient-facing oncology staff SARS-CoV-2 exposure.

Added value of this study

To the best of our knowledge, this is the first study specifically investigating SARS-CoV-2 exposure in UK patient-facing oncology staff who were at work during the peak of the COVID-19 pandemic between March and June 2020. 18·4% of staff were SARS-CoV-2 antibody positive at the start of June 2020 suggesting prior SARS-CoV-2 infection, while 32·5% of those antibody-positive cases became antibody-negative 28 days after the first sample collection. The highest seroprevalence rates at both time points were recorded in nurses.

Implications of all the available evidence

These results justify incorporating SARS-CoV-2 PCR and antibody testing of oncology nurses into international guidelines for managing cancer patients treated with non-surgical anticancer treatments prior to availability of a functional vaccine.