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1.
Preprint em Inglês | medRxiv | ID: ppmedrxiv-21251127

RESUMO

OBJECTIVESTo investigate the potential of shared sporting equipment as transmission vectors of SARS-CoV-2 during the reintroduction of sports such as soccer, rugby, cricket, tennis, golf and gymnastics. SETTINGLaboratory based live SARS-CoV-2 virus study INTERVENTIONSTen different types of sporting equipment were inoculated with 40l droplets containing clinically relevant high and low concentrations of live SARS-CoV-2 virus. Materials were then swabbed at time points relevant to sports (1, 5, 15, 30, 90 minutes). The amount of live SARS-CoV-2 recovered at each time point was enumerated using viral plaque assays, and viral decay and half-life was estimated through fitting linear models to log transformed data from each material. MAIN OUTCOME MEASUREThe primary outcome measure was quantification of retrievable SARS-CoV-2 virus from each piece of equipment at pre-determined time points. RESULTSAt one minute, SARS-CoV-2 virus was recovered in only seven of the ten types of equipment with the low dose inoculum, one at five minutes and none at 15 minutes. Retrievable virus dropped significantly for all materials tested using the high dose inoculum with mean recovery of virus falling to 0.74% at 1 minute, 0.39% at 15 minutes and 0.003% at 90 minutes. Viral recovery, predicted decay, and half-life varied between materials with porous surfaces limiting virus transmission. CONCLUSIONSThis study shows that there is an exponential reduction in SARS-CoV-2 recoverable from a range of sports equipment after a short time period, and virus is less transferrable from materials such as a tennis ball, red cricket ball and cricket glove. Given this rapid loss of viral load and the fact that transmission requires a significant inoculum to be transferred from equipment to the mucous membranes of another individual it seems unlikely that sports equipment is a major cause for transmission of SARS-CoV-2. These findings have important policy implications in the context of the pandemic and may promote other infection control measures in sports to reduce the risk of SARS-CoV-2 transmission and urge sports equipment manufacturers to identify surfaces that may or may not be likely to retain transferable virus. O_TEXTBOXWHAT IS ALREADY KNOWN ON THIS TOPICO_LITransmission of SARS-CoV-2 between individuals playing sport may be via respiratory droplets when in close proximity to an infected person. C_LIO_LISARS-CoV-2 remains viable on a variety of surfaces resulting in recommendations to reduce the sharing of sports equipment such as tennis balls when sports were re-opened. C_LI WHAT THIS STUDY ADDSO_LIThe recoverable SARS-CoV-2 viral load reduces exponentially with mean viral load of all materials less than 1% of the original inoculum after 1 minute. C_LIO_LIThe type of material has a significant effect on SARS-CoV-2 transfer, with less virus transferred from porous materials such as bovine leather or nylon woven cloth. C_LIO_LIPolicies on infection control measures in sport may be better directed towards areas other than reducing the sharing of sports equipment. C_LIO_LISports equipment manufacturers may consider using materials that absorb or retain virus as a way of reducing viral transmission from sports equipment. C_LI C_TEXTBOX

2.
Preprint em Inglês | medRxiv | ID: ppmedrxiv-20183459

RESUMO

Serological testing is emerging as a powerful tool to progress our understanding of COVID-19 exposure, transmission and immune response. Large-scale testing is limited by the need for in-person blood collection by staff trained in venepuncture. Capillary blood self-sampling and postage to laboratories for analysis could provide a reliable alternative. Two-hundred and nine matched venous and capillary blood samples were obtained from thirty nine participants and analysed using a COVID-19 IgG ELISA to detect antibodies against SARS-CoV-2. Thirty seven out of thirty eight participants were able to self-collect an adequate sample of capillary blood ([≥]50 l). Using plasma from venous blood collected in lithium heparin as the reference standard, matched capillary blood samples, collected in lithium heparin-treated tubes and on filter paper as dried blood spots, achieved a Cohen's kappa coefficient of >0.88 (near-perfect agreement). Storage of capillary blood at room temperature for up to 7 days post sampling did not affect concordance. Our results indicate that capillary blood self-sampling is a reliable and feasible alternative to venepuncture for serological assessment in COVID-19.

3.
Preprint em Inglês | medRxiv | ID: ppmedrxiv-20149534

RESUMO

RT-qPCR utilising upper respiratory swabs are the diagnostic gold standard for SARS-CoV-2 despite reported low sensitivity and limited scale up due to global shortages. Saliva is a non-invasive, equipment independent alternative to swabs. We collected 145 paired saliva and nasal/throat (NT) swabs at diagnosis (day 0) and repeated on day 2 and day 7 dependent on inpatient care and day 28 for study follow up. Laboratory cultured virus was used to determine the analytical sensitivity of spiked saliva and swabs containing amies preservation media. Self-collected saliva samples were found to be consistent, and in some cases superior when compared to healthcare worker collected NT swabs from COVID-19 suspected participants. We report for the first time the analytical limit of detection of 10-2and 100 pfu/ml for saliva and swabs respectively. Saliva is a easily self-collected, highly sensitive specimen for the detection of SARS-CoV-2.

4.
Preprint em Inglês | medRxiv | ID: ppmedrxiv-20124636

RESUMO

We report dynamics of seroconversion to SARS-CoV-2 infections detected by IgG ELISA in 177 individuals diagnosed by RT-PCR. Longitudinal analysis identifies 2-8.5% of individuals who do not seroconvert even weeks after infection. They are younger than seroconverters who have increased co-morbidity and higher inflammatory markers such as C-Reactive Protein. Higher antibody responses are associated with non-white ethnicity. Antibody responses do not decline during follow up almost to 2 months. Serological assays increase understanding of disease severity. Their application in regular surveillance will clarify the duration and protective nature of humoral responses to SARS-CoV-2.

5.
Preprint em Inglês | medRxiv | ID: ppmedrxiv-20082099

RESUMO

Here we describe an open and transparent consortium for the rapid development of COVID-19 rapid diagnostics tests. We report diagnostic accuracy data on the Mologic manufactured IgG COVID-19 ELISA on known positive serum samples and on a panel of known negative respiratory and viral serum samples pre-December 2019. In January, Mologic, embarked on a product development pathway for COVID-19 diagnostics focusing on ELISA and rapid diagnostic tests (RDTs), with anticipated funding from Wellcome Trust and DFID. 834 clinical samples from known COVID-19 patients and hospital negative controls were tested on Mologics IgG ELISA. The reported sensitivity on 270 clinical samples from 124 prospectively enrolled patients was 94% (95% CI: 89.60% - 96.81%) on day 10 or more post laboratory diagnosis, and 96% (95% CI: 84.85% - 99.46%) between 14-21 days post symptom onset. A specificity panel comprising 564 samples collected pre-December 2019 were tested to include most common respiratory pathogens, other types of coronavirus, and flaviviruses. Specificity in this panel was 97% (95% CI: 95.65% - 98.50%). This is the first in a series of Mologic products for COVID-19, which will be deployed for COVID-19 diagnosis, contact tracing and sero-epidemiological studies to estimate disease burden and transmission with a focus on ensuring access, affordability, and availability to low-resource settings.

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