Prospective surveillance of respiratory infections in British Antarctic Survey bases during the COVID-19 pandemic.

BACKGROUND: The British Antarctic bases offer a semi-closed environment for assessing the transmission and persistence of seasonal respiratory viruses. METHODS: Weekly swabbing was performed for respiratory pathogen surveillance (including SARS-CoV-2), at two British Antarctic Survey bases, during 2020: King Edward Point (KEP, 30 June-29 September, 9 participants, 124 swabs) and Rothera (9 May-6 June, 27 participants, 127 swabs). Symptom questionnaires were collected for any newly symptomatic cases that presented during this weekly swabbing period. RESULTS: At KEP, swabs tested positive for non-SARS-CoV-2 seasonal coronavirus (2), adenovirus (1) parainfluenza 3 (1) and respiratory syncytial virus B (1). At Rothera, swabs tested positive for non-SARS-CoV-2 seasonal coronavirus (3), adenovirus (2) parainfluenza 4 (1) and human metapneumovirus (1). All bacterial agents identified were considered to be colonizers and not pathogenic. CONCLUSIONS: At KEP, the timeline indicated that the parainfluenza 3 and adenovirus infections could have been linked to some of the symptomatic cases that presented. For the other viruses, the only other possible sources were the visiting ship crew members. At Rothera, the single symptomatic case presented too early for this to be linked to the subsequent viral detections, and the only other possible source could have been a single non-participating staff member.

A rapid RT-LAMP SARS-CoV-2 screening assay for collapsing asymptomatic COVID-19 transmission.

PURPOSE: To demonstrate the diagnostic performance of rapid SARS-CoV-2 RT-LAMP assays, comparing the performance of genomic versus sub-genomic sequence target with subsequent application in an asymptomatic screening population. METHODS: RT-LAMP diagnostic specificity (DSe) and sensitivity (DSe) was determined using 114 RT-PCR clinically positive and 88 RT-PCR clinically negative swab samples processed through the diagnostic RT-PCR service within the University Hospitals of Leicester NHS Trust. A swab-based RT-LAMP SARS-CoV-2 screening programme was subsequently made available to all staff and students at the University of Leicester (Autumn 2020), implemented to ISO 15189:2012 standards using NHS IT infrastructure and supported by University Hospital Leicester via confirmatory NHS diagnostic laboratory testing of RT-LAMP 'positive' samples. RESULTS: Validation samples reporting a Ct < 20 were detected at 100% DSe and DSp, reducing to 95% DSe (100% DSp) for all samples reporting a Ct < 30 (both genomic dual sub-genomic assays). Advisory screening identified nine positive cases in 1680 symptom free individuals (equivalent to 540 cases per 100,000) with results reported back to participants and feed into national statistics within 48 hours. CONCLUSION: This work demonstrates the utility of a rapid RT-LAMP assay for collapsing transmission of SARS-CoV-2 in an asymptomatic screening population.

Outbreak of SARS-CoV-2 at a hospice: terminated after the implementation of enhanced aerosol infection control measures.

Outbreaks of COVID-19 in hospices for palliative care patients pose a unique and difficult situation. Staff, relatives and patients may be possible sources and recipients of infection. We present an outbreak of COVID-19 in a hospice setting, during the UK's first pandemic wave. During the outbreak period, 26 patients and 30 staff tested SARS-CoV-2 positive by laboratory-based RT-PCR testing. Most infected staff exhibited some mild, non-specific symptoms so affected staff members may not have voluntarily self-isolated or had themselves tested on this basis. Similarly, for infected patients, most became symptomatic and were then isolated. Additional, enhanced aerosol infection control measures were implemented, including opening of all windows where available; universal masking for all staff, including in non-clinical areas and taking breaks separately; screening for asymptomatic infection among staff and patients, with appropriate isolation (at home for staff) if infected; performing a ventilation survey of the hospice facility. After these measures were instigated, the numbers of COVID-19 cases decreased to zero over the following three weeks. This outbreak study demonstrated that an accurate understanding of the routes of infection for a new pathogen, as well as the nature of symptomatic versus asymptomatic infection and transmission, is crucial for controlling its spread.

Clinical utility of a rapid 'on-demand' laboratory-based SARS-CoV-2 diagnostic testing service in an acute hospital setting admitting COVID-19 patients.

BACKGROUND: With the onset of the COVID-19 pandemic in 2020, hospital clinical teams have realised that there is a need for a rapid, accurate testing facility that will allow them to move patients quickly into isolation rooms or specific COVID-19 cohort wards as soon as possible after admission. METHODS: Starting from July 2020, PCR-based test platforms, which could test 4-8 samples in parallel with turnaround (sample-to-result) times of 50-80 min, were placed in a satellite laboratory. This laboratory was on the same floor and within walking distance to the acute respiratory admissions ward. It was staffed by a team of three mid-Band 4 staff that split a 0700-2200 h-work day, 7 days a week, with 2 senior supervisors. Urgent sample testing was decided upon by the clinical teams and requested by phone. The test results were entered manually in real-time as they became available, and sent electronically to the requesting ward teams. RESULTS: The daily/monthly PCR positive test numbers approximately followed the local and national UK trend in COVID-19 case numbers, with the daily case numbers being reflective of the November and December 2020 surges. Test results were used to rapidly segregate positive patients into dedicated COVID-19 ward areas to minimise risk of potential nosocomial transmission in crowded waiting areas. Testing capacity was sufficient to include cases with uncertain diagnosis likely to require hospital admission. Following completion of other admission processes, based on these rapid test results, patients were allocated to dedicated COVID-19 positive or negative cohort wards. CONCLUSIONS: This rapid testing facility reduced unnecessary 'length-of-stay' in a busy acute respiratory ward. In the current absence of a treatment for mild-to-moderate COVID-19, on which patients could be discharged home to complete, the rapid test facility has become a successful aid to patient flow and reduced exposure and nosocomial transmission.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroconversion in hematology-oncology patients.

Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China at the end of 2019, the virus has spread rapidly across the globe leading to millions of infections and subsequent deaths. Although the virus infects those exposed indiscriminately, there are groups in society at an increased risk of severe infection, leading to increased morbidity. Patients suffering from hematological cancers, particularly leukemia, lymphoma, and myeloma, may be one such group and previous studies have suggested that they may be at a three to four times greater risk of severe COVID-19 after SARS-CoV-2 infection, leading to admissions to ICU, mechanical ventilation, and death compared to those without such malignancies. Serological testing for IgG seroconversion has been extensively studied in the immunocompetent, but fewer publications have characterized this process in large series of immunocompromised patients. This study described 20 patients with hematological cancers who tested positive for SARS-CoV-2 via PCR with 12 of the patients receiving further serological testing. We found that of the 12 patients screened for SARS-CoV-2 IgG antibodies, only 2 (16.6%) were able to generate an immune response to the infection. Yet despite this low seroconversion rate in this cohort, none of these patients died or became particularly unwell with COVID-19 or its related complications.