Serological prevalence of antibodies to SARS CoV-2 amongst cancer centre staff
Objectives: the aim of this study was to test Rutherford Health (RH) staff for the presence of SARS CoV-2 antibodies to reduce the risk of infection to cancer patients. Setting: Between 14 and 24 April 2020 we tested 161 staff at four locations: our cancer centres in Reading - Berkshire, Newport - S Wales, Liverpool - Merseyside, and Bedlington in Northumberland. Participants: Testing was available to all staff who were on site at the four locations named above at the time the study was carried out. 161 staff (80 men, 81 women) gave voluntary consent to have the tests and all testing gave rise to valid results. Interventions: We used the South Korean test for antibodies to SARS CoV-2: Sugentech SGTi-flex COVID-19 IgM/IgG1. For each test, blood was collected and added to the sample well of the test cassette and buffer solution added. The test result was legible after 15 minutes. Outcome measures: The number of tests positive for the presence of antibodies was the primary outcome measure. The ratio of tests positive for the presence of IgM antibodies versus IgG antibodies was the secondary outcome measure. Results: Between 14 and 24 April 2020, 161 staff (age m = 43) were tested at four Rutherford Cancer Care centres that offer proton beam therapy, radiotherapy and chemotherapy. Out of 161, 12 samples (7.50%) tested positive of which 7 samples (4.35%) detected IgM only, 2 samples (1.24%) detected IgG only and 3 samples (1.86%) detected both IgM and IgG. Conclusions: The low seroconversion rate in the sample population limits the current utility of the test as a way of reducing risk to vulnerable patient populations but longitudinal retesting will provide further data.