Comparison between mid-nasal swabs and buccal swabs for SARS-CoV-2 detection in mild COVID-19 patients

BackgroundThe use of rapid antigen diagnostics tests (Ag-RDT) has gained widespread acceptance as an alternative method for diagnosis of COVID-19 outside of health care settings. Various authors have reported that saliva is a reliable specimen, alternative to nasopharyngeal and mid-nasal swabs, to detect SARS-CoV-2 infections by RT-PCR. We assessed the performance of buccal swabs containing saliva for SARS-CoV-2 detection by Ag-RDT, using mid-nasal specimens as a reference in the northern area of Barcelona (Catalonia, Spain) MethodsIn the context of routine clinical diagnosis of mild COVID-19 patients, we enrolled 300 adults in a study to directly compare mid-nasal swabs and saliva specimens for SARS-CoV-2 detection by Ag-RDT.. When mid-nasal and buccal Ag-RDTs showed discordant results, a third mid-nasal swab was collected and analysed by RT-PCR. ResultsPaired samples were successfully obtained in 300 suspected cases of SARS-CoV-2 infection. Of the 300 paired samples, Ag-RDT with the mid-nasal swab detected 139 (46.3%) positive COVID-19 cases. In comparison, buccal swabs showed a sensitivity and specificity of 31.7% (44/139) and 98.8% (159/161), respectively. 65 discordant results with positive mid-nasal swabs and negative buccal swabs were tested by RT-qPCR. All samples tested by Rt-PCR resulted positive, with a mean cycle threshold (Ct) of 28.3 (SD 7.3). ConclusionOur findings show that mid-nasal swabs have better performance than buccal swabs for detecting SARS-CoV-2 with Ag-RDT tests. Of note, the sensitivity of buccal samples was affected in samples with high viral loads (Ct<33), suggesting that buccal swabs might not be sensitive enough to detect individuals at risk of transmission. Taken together, the existing literature and the results provided in our analysis we advise against the use of buccal specimens for SARS-CoV-2 diagnostics with Ag-RDT.

Convalescent plasma for outpatients with early COVID-19

BackgroundConvalescent plasma (CP) for hospitalized patients with COVID-19 has not demonstrated clear benefits. However, data on outpatients with early symptoms are scarce. We aimed to assess whether treatment with CP administered during the first 7 days of symptoms reduced the disease progression or risk of hospitalization of outpatients. MethodsTwo double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when <20% of their predefined sample size had been recruited. A Bayesian adaptive individual patient data meta-analysis was implemented. Analyses were done with Bayesian proportional odds and logistic models, where odds ratios (OR)<1.0 indicate a favorable outcome for CP. Fourteen study sites across the Netherlands and Catalonia in Spain participated in the trial. The two studies included outpatients aged [≥]50 years and diagnosed with COVID-19 and symptomatic for [≤]7days. The intervention consisted of one unit (200-300mL) of CP with a predefined minimum level of antibodies. The two primary endpoints were (a) a 5-point disease severity scale (fully recovered by day 7 or not, hospital or ICU admission and death) and (b) a composite of hospitalization or death. ResultsOf 797 patients included, 390 received CP and 392 placebo. At baseline, they had a median age of 58 years, 1 comorbidity, symptoms for 5 days and 93% tested negative for SARS-CoV-2 S-protein IgG antibodies. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The OR of CP for an improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311). The OR for hospitalization or death was 0.919 (CI 0.592-1.416). The effect of CP on hospital admission or death was largest in patients with [≤]5 days of symptoms (OR 0.658, 95% CI 0.394-1.085). CP did not decrease the time to full symptom resolution (p=0.62). ConclusionTreatment with CP of outpatients in the first 7 days of symptoms did not improve the outcome of COVID-19. The possible beneficial effect in patients with [≤]5 days of symptoms requires further study. RegistrationNCT04621123 and NCT04589949 on https://www.clinicaltrials.gov Funding sourceZONMW, the Netherlands, grant number 10430062010001. SUPPORT-E, grant number 101015756 YoMeCorono, www.tomecorono.com The Fight AIDS and Infectious Diseases Foundation with funding from the pharmaceutical company Grifols S.A

Antibody kinetics to SARS-CoV-2 at 13.5 months, by disease severity

BackgroundUnderstanding humoral responses and seroprevalence in SARS-CoV-2 infection is essential for guiding vaccination strategies in both infected and uninfected individuals. MethodsWe determine the kinetics of IgM against the nucleocapsid (N) and IgG against the spike (S) and N proteins of SARS-CoV-2 in a cohort of 860 health professionals (healthy and infected) in northern Barcelona. We model the kinetics of IgG and IgM at nine time points over 13.5 months from infection, using non-linear mixed models by sex and clinical disease severity. ResultsOf the 781 participants who were followed up, 478 (61.2%) became infected with SARS-CoV-2. Significant differences were found for the three antibodies by disease severity and sex. At day 270 after diagnosis, median IgM(N) levels were already below the positivity threshold in patients with asymptomatic and mild-moderate disease, while IgG(N, S) levels remained positive to days 360 and 270, respectively. Kinetic modelling showed a general rise in both IgM(N) and IgG(N) levels up to day 30, followed by a decay whose rate depended on disease severity. IgG(S) levels increased at day 15 and remained relatively constant over time. ConclusionsWe describe kinetic models of IgM(N) and IgG(N, S) SARS-CoV-2 antibodies at 13.5 months from infection and disease spectrum. Our analyses delineate differences in the kinetics of IgM and IgG over a year and differences in the levels of IgM and IgG as early as 15 days from symptoms onset in severe cases. These results can inform public health policies around vaccination criteria. Funded by the regional Ministry of Health of the Generalitat de Catalunya (Call COVID19-PoC SLT16_04; NCT04885478)

SARS-CoV-2 B.1.351 (beta) variant shows enhanced infectivity in K18-hACE2 transgenic mice and expanded tropism to wildtype mice compared to B.1 variant

SARS-CoV-2 variants display enhanced transmissibility and/or immune evasion and can be generated in humans or animals, like minks, thus generating new reservoirs. The continuous surveillance of animal susceptibility to new variants is necessary to predict pandemic evolution. In this study we demonstrate that, compared to the B.1 SARS-CoV-2 variant, K18-hACE2 transgenic mice challenged with the B.1.351 variant displayed a faster progression of infection. Furthermore, we also report that B.1.351 can establish infection in wildtype mice, while B.1 cannot. B.1.351-challenged wildtype mice showed a milder infection than transgenic mice, confirmed by detectable viral loads in oropharyngeal swabs and tissues, lung pathology, immunohistochemistry and serology. In silico models supported these findings by demonstrating that the Spike mutations in B.1.351 resulted in increased affinity for both human and murine ACE2 receptors. Overall, this study highlights the plasticity of SARS-CoV-2 animal susceptibility landscape, which may contribute to viral persistence and expansion.

Siglec-1 on dendritic cells mediates SARS-CoV-2 trans-infection of target cells while on macrophages triggers proinflammatory responses

COVID-19 pandemic is not yet under control by vaccination, and effective antivirals are critical for preparedness. Here we report that macrophages and dendritic cells, key antigen presenting myeloid cells (APCs), are largely resistant to SARS-CoV-2 infection. APCs effectively captured viruses within cellular compartments that lead to antigen degradation. Macrophages sense SARS-CoV-2 and released higher levels of cytokines, including those related to cytokine storm in severe COVID-19. The sialic acid-binding Ig-like lectin 1 (Siglec-1/CD169) present on APCs, which interacts with sialylated gangliosides on membranes of retroviruses or filoviruses, also binds SARS-CoV-2 via GM1. Blockage of Siglec-1 receptors by monoclonal antibodies reduces SARS-CoV-2 uptake and transfer to susceptible target cells. APCs expressing Siglec-1 and carrying SARS-CoV-2 are found in pulmonary tissues of non-human primates. Single cell analysis reveals the in vivo induction of cytokines in those macrophages. Targeting Siglec-1 could offer cross-protection against SARS-CoV-2 and other enveloped viruses that exploit APCs for viral dissemination, including those yet to come in future outbreaks.

Effect of mesenchymal stromal cells encapsulated within polyethylene glycol-collagen hydrogels formed in situ on alkali-burned corneas in an ex vivo organ culture model.

BACKGROUND AIMS: Corneal inflammation after alkali burns often results in vision loss due to corneal opacification and neovascularization. Mesenchymal stem cells (MSCs) and their secreted factors (secretome) have been studied for their anti-inflammatory and anti-angiogenic properties with encouraging results. However, topical instillation of MSCs or their secretome is often accompanied by issues related to delivery or rapid washout. Polyethylene glycol (PEG) and collagen are well-known biomaterials used extensively in scaffolds for tissue engineering. To effectively suppress alkaline burn-induced corneal injury, the authors proposed encapsulating MSCs within collagen gels cross-linked with multi-functional PEG-succinimidyl esters as a means to deliver the secretome of immobilized MSCs. METHODS: Human MSCs were added to a neutralized collagen solution and mixed with a solution of four-arm PEG-N-hydroxysuccinimide. An ex vivo organ culture was conducted using rabbit corneas injured by alkali burn. MSCs were encapsulated within PEG-collagen hydrogels and injected onto the wounded cornea immediately following alkali burn and washing. Photographs of the ocular surface were taken over a period of 7 days after the alkali burn and processed for immunohistochemical evaluation. Samples were split into three groups: injury without treatment, MSCs alone, and MSCs encapsulated within PEG-collagen hydrogels. RESULTS: All corneas in ex vivo organ culture lost their transparency immediately after alkali burn, and only the groups treated with MSCs and MSCs encapsulated within PEG-collagen hydrogels recovered some transparency after 7 days. Immunohistochemical analysis revealed increased expression of vimentin in the anterior corneal stroma of the group without treatment indicative of fibrotic healing, whereas less stromal vimentin was detected in the group containing MSCs encapsulated within the PEG-collagen hydrogels. CONCLUSIONS: PEG-collagen hydrogels enable the encapsulation of viable MSCs capable of releasing secreted factors onto the ocular surface. Encapsulating MSCs within PEG-collagen hydrogels may be a promising method for delivering their therapeutic benefits in cases of ocular inflammatory diseases, such as alkali burn injuries.

Previous SARS-CoV-2 infection increases B.1.1.7 cross-neutralization by vaccinated individuals.

To assess the potential impact of predominant circulating SARS-CoV-2 variants on neutralizing activity of infected and/or vaccinated individuals, we analyzed neutralization of pseudoviruses expressing the spike of the original Wuhan strain, the D614G and B.1.1.7 variants. Our data show that parameters of natural infection (time from infection and infecting variant) determined cross-neutralization. Importantly, upon vaccination, previously infected individuals developed equivalent B.1.1.7 and Wuhan neutralizing responses. In contrast, uninfected vaccinees showed reduced neutralization against B.1.1.7. FundingThis study was funded by Grifols, the Departament de Salut of the Generalitat de Catalunya, the Spanish Health Institute Carlos III, CERCA Programme/Generalitat de Catalunya, and the crowdfunding initiatives #joemcorono, BonPreu/Esclat and Correos.

Performance characteristics of five antigen-detecting rapid diagnostic test (Ag-RDT) for SARS-CoV-2 asymptomatic infection: a head-to-head benchmark comparison

Background Mass testing for early identification and isolation of infectious COVID-19 individuals, irrespective of concurrent symptoms, is an efficacious strategy to reduce disease transmission. Antigen-detecting rapid diagnostic tests (Ag-RDT) appear as a potentially suitable tool for mass testing on account of their ease-of-use, fast turnaround time, and low cost. However, benchmark comparisons are scarce, particularly in the context of unexposed asymptomatic individuals. Methods We used nasopharyngeal specimens from unexposed asymptomatic individuals to assess five Ag-RDTs: PanBio™ COVID-19 Ag Rapid test (Abbott), CLINITEST® Rapid COVID-19 Antigen Test (Siemens), SARS-CoV-2 Rapid Antigen Test (Roche Diagnostics), SARS-CoV-2 Antigen Rapid Test Kit (Lepu Medical), and COVID-19 Coronavirus Rapid Antigen Test Cassette (Surescreen). Samples were collected between December 2020-January 2021 during the third wave of the epidemic in Spain. Findings The analysis included 101 specimens with confirmed positive PCR results and 185 with negative PCR. For the overall sample, the performance parameters of Ag-RDTs were as follows: Abbott assay, sensitivity 38·6% (95% CI 29·1–48·8) and specificity 99·5% (97–100%); Siemens, sensitivity 51·5% (41·3–61·6) and specificity 98·4% (95·3–99·6); Roche, sensitivity 43·6% (33·7–53·8) and specificity 96·2% (92·4–98·5); Lepu, sensitivity 45·5% (35·6–55·8) and specificity 89·2% (83·8–93·3%); Surescreen, sensitivity 28·8% (20·2–38·6) and specificity 97·8% (94·5–99·4%). For specimens with cycle threshold (Ct) <30 in RT-qPCR, all Ag-RDT achieved a sensitivity of at least 70%, with Siemens, Roche, and Lepu assays showing sensitivities higher than 80%. In models according to population prevalence, all Ag-RDTs will have a NPV >99% and a PPV<50% at 1% prevalence. Interpretation Two commercial, widely available assays can be used for SARS-CoV-2 antigen testing to achieve sensitivity in specimens with a Ct<30 and specificity of at least 80% and 96%, respectively. Estimated negative and positive predictive values suggests the suitability of Ag-RDTs for mass screenings of SARS-CoV-2 infection in the general population. Funding Blueberry diagnostics, Fundació Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, and #YoMeCorono.org crowdfunding campaign. Evidence before this study In December 2020, we searched on PubMed for articles containing the terms “antigen”, “test” (or Ag-RDT), and “SARS-CoV-2” or “COVID-19” either in the title or the abstract. Our search yielded 79 entries corresponding to articles written in English. Of them, 33 were articles presenting the diagnostic performance of qualitative lateral-flow antigen-detecting rapid diagnostic tests (Ag-RDT). Four of these articles reported the results of head-to-head comparisons of various Ag-RDTs; in all cases, the number of tests was lower than the recommended for retrospective assessments of diagnostic performance (i.e., minimum of 100 PCR positive and 100 PCR negative). Furthermore, all head-to-head comparisons found in the literature included specimens obtained among individuals with varying disease status (none of which asymptomatic), thus limiting the adequacy of the estimates for an asymptomatic screening strategy. Added value of this study We compared for the first time head-to-head five Ag-RDT using a powered set of fresh respiratory specimens PCR-confirmed positive or negative, collected from unexposed asymptomatic individuals during screening campaigns for early detection of SARS-CoV-2 infection. The sample size was large enough to draw robust conclusions. Our analysis identified four Ag-RDTs (i.e., assays marketed by Abbott, Siemens, Roche, and Surescreen) with specificity higher than 96%. Despite the low sensitivity for the overall sample (range 29% to 51%), the corresponding values for the subset of samples with Ct <30 were higher than 80% for Siemens, Roche, and Lepu assays. The estimated NPV for a screening performed in an area with 1% prevalence would be >99% for all tests, while the PPV would be <50%. Implications of all the available evidence Current data on the diagnostic performance of Ag-RDTs is heterogeneous and precludes benchmark assessments. Furthermore, the screening of asymptomatic populations is currently not considered among the intended uses of Ag-RDT, mostly because of lack of evidence on test performance in samples from unexposed asymptomatic individuals. Our findings add to the current evidence in two ways: first, we provide benchmarking data on Ag-RDTs, assessed head-to-head in a single set of respiratory specimens; second, we provide data on the diagnostic performance of Ag-RDTs in unexposed asymptomatic individuals. Our findings support the idea that Ag-RDTs can be used for mass screening in low prevalence settings and accurately rule out a highly infectious case in such setting.

3D Printable, Modified Trephine Designs for Consistent Anterior Lamellar Keratectomy Wounds in Rabbits.

PURPOSE: Our goal is to develop a low-cost tool that can be used to create consistent, partial-thickness defects in rabbit and other large animals with minimal surgical training and that can facilitate pre-clinical testing of lamellar and in situ-forming biosynthetic matrix materials for corneal repair. MATERIALS & METHODS: In this study, three modified trephines were designed to create deep corneal wound defects with consistent depth in large animals. The modified trephines incorporated either 3D-printed parts made from photopolymerizable resins, or custom-cut commercially available Teflon sheets. Wound defects were imaged with optical coherence tomography (OCT), and the depth was analyzed based on the OCT images. RESULTS: The results revealed that an inner-stopper guard trephine had the best performance in creating consistent and precise wound defect depth compared to modified vacuum trephine and custom guard vacuum trephine. A 75% ± 10% cut of the cornea was achieved with the inner-stopper guard trephine. The wound defect depth by created by the inner-stopper guard trephine was independent of the corneal thickness or size of the globes. Although the cut depth of the inner-stopper guard trephine differed by the experience-level of its users, the consistency (standard deviation) of the depth was independent of experience. CONCLUSIONS: Our studies provided three cost-efficient animal trephines that can create corneal wounds of consistent depth by lab researchers without extensive training in keratectomy.

Seroprevalence of SARS-CoV-2 IgG Specific Antibodies among Healthcare Workers in the Northern Metropolitan Area of Barcelona, Spain, after the first pandemic wave

BackgroundThe rapid spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) around the world has caused a global pandemic, infecting millions of individuals worldwide, with an unprecedented impact in health care systems worldwide. Healthcare workers are one of the risk groups that need to be well characterized due to their strategic role in the management of patients, presently and in prevention of healthcare needs for future outbreaks. This study presents the results of the first SARS-CoV-2 seroprevalence study in the Northern Metropolitan Area of Barcelona, Spain. MethodsIgG SARS-CoV2 antibodies were analyzed in serum samples from 7563 healthcare workers of the Northern Metropolitan Area of Barcelona taken during the pandemia (from May 4th to May 22nd, 2020) by chemiluminescence assays. ResultsA total of 779 of 7563 (10.3%) healthcare workers had detectable anti-SARS-CoV-2 IgG (specific for either S1/S2 or N antigens). No significant differences were observed between those working at primary care or at the reference hospital. Interestingly, in 29 (8.53%) of the previously confirmed positive reverse-transcriptase polymerase chain reaction (rRT-PCR) patients SARS-CoV-2 IgG (S1/S2 or recombinant N antigen) were negative. ConclusionSeroprevalence of anti-SARS-CoV-2 IgG in the healthcare workers of the Nord Metropolitan Area of Barcelona was significantly increased in comparison with the general population in the same geographical area. These results give us an important insight for a better understanding of SARS-CoV-2 epidemiology, in a collective that is essential for the response against this pandemic.

Search for SARS-CoV-2 inhibitors in currently approved drugs to tackle COVID-19 pandemia

There is an urgent need to identify therapeutics for the treatment of Coronavirus diseases 2019 (COVID-19). Although different antivirals are given for the clinical management of SARS-CoV-2 infection, their efficacy is still under evaluation. Here, we have screened existing drugs approved for human use in a variety of diseases, to compare how they counteract SARS-CoV-2-induced cytopathic effect and viral replication in vitro. Among the potential 72 antivirals tested herein that were previously proposed to inhibit SARS-CoV-2 infection, only 18% had an IC50 below 25 M or 102 IU/mL. These included plitidepsin, novel cathepsin inhibitors, nelfinavir mesylate hydrate, interferon 2-alpha, interferon-gamma, fenofibrate, camostat along the well-known remdesivir and chloroquine derivatives. Plitidepsin was the only clinically approved drug displaying nanomolar efficacy. Four of these families, including novel cathepsin inhibitors, blocked viral entry in a cell-type specific manner. Since the most effective antivirals usually combine therapies that tackle the virus at different steps of infection, we also assessed several drug combinations. Although no particular synergy was found, inhibitory combinations did not reduce their antiviral activity. Thus, these combinations could decrease the potential emergence of resistant viruses. Antivirals prioritized herein identify novel compounds and their mode of action, while independently replicating the activity of a reduced proportion of drugs which are mostly approved for clinical use. Combinations of these drugs should be tested in animal models to inform the design of fast track clinical trials.

Crecimiento post-traumático en supervivientes de cáncer y sus otros significativos: ¿crecimiento vicario o secundario? / Posttraumatic growth in cancer survivors and their significant others: vicarious or secondary growth?

Las enfermedades graves como el cáncer, aunque generan elevado malestar emocional y estrés en los supervivientes y en sus otros significativos, también pueden suponer un estímulo en la generación de crecimiento postraumático en ambos. Los mecanismos de cómo se produce este crecimiento postraumático (vicario vs. secundario) en los otros significativos no se han estudiado. En esta revisión se analizan la evidencia y relación del crecimiento post-traumático en supervivientes de cáncer y en sus otros significativos, principalmente sus parejas, madres y padres, en relación a estos mecanismos de transmisión vicario o secundario. Se concluye que, en general, el crecimiento post-traumático en los otros significativos es una experiencia vicaria íntimamente ligada al crecimiento del superviviente en cáncer, aunque ser mujer, madre o sufrir un cáncer avanzado facilitan procesos de crecimiento post-traumático secundario en los otros significativos, que se diferencian del superviviente.

Severe diseases such as cancer although generate high stress and emotional distress in survivors and their significant others, can also be a stimulus to promote posttraumatic growth. The mechanisms of this post-traumatic growth (vicarious vs secondary) in significant others have not been studied. This review examines the evidence and relationship between posttraumatic growth in cancer survivors and their significant others, mainly in their partners and parents, regarding these vicarious or secondary growth transmission mechanisms. We conclude that, in general, posttraumatic growth in significant others is a vicarious experience closely linked to the cancer survivor's growth. However, being a woman, mother or suffer an advanced cancer facilitate secondary posttraumatic growth processes insignificant others.

Low frequency of recurrent BRCA1 and BRCA2 mutations in Spain.

BRCA1 and BRCA2 mutations underlie a substantial proportion of all hereditary breast cancer. The mutational spectrum in these genes is very broad, with hundreds of different BRCA mutations reported worldwide. However, high frequency founder mutations make up a substantial fraction of all mutations in some ethnic groups. We directly sequenced BRCA1 and BRCA2 in 35 Spanish breast/ovarian cancer families and found 13 mutations of which 3 had been reported previously in Spain. The ten novel mutations are: IVS5+1 G>A, 1491delA, Leu1086Ter, and Gln895Ter in BRCA1; Glu49Ter, 5373delGTAT, 5947delCTCT, 6672delTA, 8281insA, and Pro3039Leu (which also involves a splice site) in BRCA2. Our data, in combination with previous reports, indicate that 14 mutations have been seen recurrently in Spanish families. Analyzing these 14 mutations in 42 previously untested breast/ovarian cancer families revealed only two families testing positive, one for BRCA1 185delAG and one for BRCA2 9254delATCAT. While several mutations have been found recurrently in Spain, none appear to be high frequency founder mutations based on studies of breast and ovarian cancer families.