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2.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-330053

ABSTRACT

Purpose: Todemonstrate 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 sensitivity (DSe) and specificity (DSp) 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 standardsusing 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 genomicdual 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 statisticswithin 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.

3.
Interface Focus ; 12(2): 20210066, 2022 Apr 06.
Article in English | MEDLINE | ID: covidwho-1713823

ABSTRACT

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.

4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-305336

ABSTRACT

This study demonstrates the diagnostic performance of SARS-CoV-2 RT-LAMP assays, comparing the performance of genomic versus sub-genomic sequence target with subsequent application in an asymptomatic screening population. An RT-LAMP workflow was developed using synthetic positive control RNA and the diagnostic sensitivity and specificity was then determined using clinical patient samples processed through the diagnostic RT-PCR service within the University Hospitals of Leicester NHS Trust. 92 RT-PCR clinically positive and 88 RT-PCR clinically negative swab samples along with 78 clinically positive and 63 clinically negative saliva samples were equally detected at 100% DSe and 100% DSp for all samples reporting a Ct < 20. DSe for all samples reporting a Ct < 30 reduced slightly to around 95% (100% DSp) for both the single genomic (large open reading frame;orf1a) and dual sub-genomic (nucleocapsid plus envelope) targeting RT-LAMP assays. Lastly, the diagnostic performance of a saliva direct workflow was only about 50% that of the saliva RNA extraction workflow. Subsequently, a swab based RNA -RT-LAMP assay was implemented to ISO 15189:2012 standards supporting an advisory COVID-19 screening program for staff and students at the University of Leicester between October and December 2020. Within a 24-hour period, total nucleic acid extraction was followed by genomic target RT-LAMP plus an internal total RNA control to mitigate the possibility of false negative reporting. SARS-CoV-2 RT-LAMP positive samples were confirmed by an RT-PCR test in an NHS diagnostic laboratory and results were included within national statistics. Nine confirmed positive samples were detected in 1680 symptom free individuals (equivalent to 540 cases per 100,000) thus demonstrating the utility of RT-LAMP molecular diagnostic tool for the detection of SARS-CoV-2 in an asymptomatic population.

6.
J Med Virol ; 93(10): 6050-6053, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1432433

ABSTRACT

During the "first wave" of the coronavirus disease 2019 (COVID-19) pandemic in the United Kingdom (March-June 2020), the city of Leicester was particularly hard hit, resulting in reimposed lockdown measures. Although initial polymerase chain reaction testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was attempted within the community, testing was soon abandoned due to an inability to keep up with demand by local laboratories. It is therefore feasible that undiagnosed transmission of COVID-19 in the community by asymptomatic individuals was a real possibility. Therefore, retrospective SARS-CoV-2 immunoglobulin G (IgG) testing of archived sera from out-patients visiting University Hospitals of Leicester NHS Trust service was performed to investigate the transmission of SARS-CoV-2 in the community. A total of 1779 sera samples were tested from samples collected between 16th March and 3rd June 2020, of which 202 (11.35%) were SARS-CoV-2 IgG positive. Positivity was lowest in March (2.54%) at the beginning of the pandemic before peaking in April (17.16%) before a decline in May and June (11.16% and 12.68%, respectively). This retrospective screening offers some insight into the early patterns of SARS-CoV-2 transmission within a sampled community population during the first wave of the COVID-19 pandemic; supporting the argument for more community screening during high incidences of pandemics.


Subject(s)
Antibodies, Viral/blood , COVID-19/diagnosis , COVID-19/epidemiology , Immunoglobulin G/blood , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Immunologic Tests , Infant , Infant, Newborn , Male , Mass Screening/statistics & numerical data , Middle Aged , Pandemics , Retrospective Studies , United Kingdom/epidemiology , Young Adult
7.
J Infect ; 83(1): 119-145, 2021 07.
Article in English | MEDLINE | ID: covidwho-1386031

ABSTRACT

We performed a retrospective screening of 428 serum samples for anti-SARS-CoV-2  immunoglobulin during a period of low prevalence. Employing two different serological tests yielded discrepant results for 10 samples; highlighting an increased risk of potential  false positive results and the need for further confirmatory testing before publication of data.


Subject(s)
COVID-19 , SARS-CoV-2 , Brazil , False Positive Reactions , Humans , Immunoglobulins , Prevalence , Retrospective Studies , Sensitivity and Specificity
9.
Clin Infect Pract ; 12: 100086, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1336339

ABSTRACT

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.

10.
J Med Virol ; 93(7): 4585-4591, 2021 07.
Article in English | MEDLINE | ID: covidwho-1263090

ABSTRACT

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.


Subject(s)
Antibodies, Viral/blood , COVID-19/pathology , Hematologic Neoplasms/immunology , Immunocompromised Host/immunology , SARS-CoV-2/immunology , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , COVID-19/diagnosis , COVID-19/immunology , COVID-19 Testing , Disease Susceptibility/immunology , Disease Susceptibility/virology , Female , Hematologic Neoplasms/drug therapy , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Retrospective Studies , Seroconversion
13.
J Med Virol ; 93(7): 4585-4591, 2021 07.
Article in English | MEDLINE | ID: covidwho-1162824

ABSTRACT

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.


Subject(s)
Antibodies, Viral/blood , COVID-19/pathology , Hematologic Neoplasms/immunology , Immunocompromised Host/immunology , SARS-CoV-2/immunology , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , COVID-19/diagnosis , COVID-19/immunology , COVID-19 Testing , Disease Susceptibility/immunology , Disease Susceptibility/virology , Female , Hematologic Neoplasms/drug therapy , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Retrospective Studies , Seroconversion
14.
J Infect ; 82(6): 253-259, 2021 06.
Article in English | MEDLINE | ID: covidwho-1152506

ABSTRACT

BACKGROUND: Human to human transmission of SARS-CoV-2 is driven by the respiratory route but little is known about the pattern and quantity of virus output from exhaled breath. We have previously shown that face-mask sampling (FMS) can detect exhaled tubercle bacilli and have adapted its use to quantify exhaled SARS-CoV-2 RNA in patients admitted to hospital with Coronavirus Disease-2019 (COVID-19). METHODS: Between May and December 2020, we took two concomitant FMS and nasopharyngeal samples (NPS) over two days, starting within 24 h of a routine virus positive NPS in patients hospitalised with COVID-19, at University Hospitals of Leicester NHS Trust, UK. Participants were asked to wear a modified duckbilled facemask for 30 min, followed by a nasopharyngeal swab. Demographic, clinical, and radiological data, as well as International Severe Acute Respiratory and emerging Infections Consortium (ISARIC) mortality and deterioration scores were obtained. Exposed masks were processed by removal, dissolution and analysis of sampling matrix strips fixed within the mask by RT-qPCR. Viral genome copy numbers were determined and results classified as Negative; Low: ≤999 copies; Medium: 1000-99,999 copies and High ≥ 100,000 copies per strip for FMS or per 100 µl for NPS. RESULTS: 102 FMS and NPS were collected from 66 routinely positive patients; median age: 61 (IQR 49 - 77), of which FMS was positive in 38% of individuals and concomitant NPS was positive in 50%. Positive FMS viral loads varied over five orders of magnitude (<10-3.3 x 106 genome copies/strip); 21 (32%) patients were asymptomatic at the time of sampling. High FMS viral load was associated with respiratory symptoms at time of sampling and shorter interval between sampling and symptom onset (FMS High: median (IQR) 2 days (2-3) vs FMS Negative: 7 days (7-10), p = 0.002). On multivariable linear regression analysis, higher FMS viral loads were associated with higher ISARIC mortality (Medium FMS vs Negative FMS gave an adjusted coefficient of 15.7, 95% CI 3.7-27.7, p = 0.01) and deterioration scores (High FMS vs Negative FMS gave an adjusted coefficient of 37.6, 95% CI 14.0 to 61.3, p = 0.002), while NPS viral loads showed no significant association. CONCLUSION: We demonstrate a simple and effective method for detecting and quantifying exhaled SARS-CoV-2 in hospitalised patients with COVID-19. Higher FMS viral loads were more likely to be associated with developing severe disease compared to NPS viral loads. Similar to NPS, FMS viral load was highest in early disease and in those with active respiratory symptoms, highlighting the potential role of FMS in understanding infectivity.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Masks , Middle Aged , RNA, Viral , Viral Load
16.
J Med Virol ; 92(11): 2880-2886, 2020 11.
Article in English | MEDLINE | ID: covidwho-935153

ABSTRACT

Coronavirus disease 2019 (COVID-19) is generally a relatively mild illness in children. An emerging disease entity coined as pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) has been reported recently, but is very rare and only affects a very small minority of children. Here we describe the clinical presentations and outcomes of three teenagers with serologically-confirmed SARS-CoV-2 infection admitted to a pediatric intensive care unit for PIMS-TS. Although their initial presentations were very similar, their COVID-19-related disease varied in severity.


Subject(s)
COVID-19/diagnosis , COVID-19/physiopathology , Systemic Inflammatory Response Syndrome/diagnosis , Systemic Inflammatory Response Syndrome/physiopathology , Adolescent , COVID-19/therapy , COVID-19 Serological Testing , Female , Humans , Intensive Care Units/statistics & numerical data , Male , Severity of Illness Index , Systemic Inflammatory Response Syndrome/therapy , United Kingdom
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