Negative Nasopharyngeal Swab Research Articles

Screening for SARS-CoV-2 in potential deceased organ donors

We read with interest the case report by Kaul and colleagues detailing a proven case of transmission of SARS-CoV-2 from a lung donor with a negative nasopharyngeal swab (NPS) to a recipient in the United States (1). A surgeon who reported possible exposure to the patient's respiratory secretions, but none of the other staff involved, also became infected.

Low utilisation of bronchoscopy to assess COVID-19 respiratory infection: a multicenter experience

ObjectiveFor the diagnosis of COVID-19, the yield of nasopharyngeal (NP) swabs is unclear, and bronchoalveolar lavage (BAL) is obtained to confirm the diagnosis. We assessed the utilisation of bronchoscopy for...

A mass spectrometry-based targeted assay for detection of SARS-CoV-2 antigen from clinical specimens.

BackgroundThe COVID-19 pandemic caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has overwhelmed health systems worldwide and highlighted limitations of diagnostic testing. Several types of diagnostic tests including RT-PCR-based assays and antigen detection by lateral flow assays, each with their own strengths and weaknesses, have been developed and deployed in a short time.MethodsHere, we describe an immunoaffinity purification approach followed a by high resolution mass spectrometry-based targeted qualitative assay capable of detecting SARS-CoV-2 viral antigen from nasopharyngeal swab samples. Based on our discovery experiments using purified virus, recombinant viral protein and nasopharyngeal swab samples from COVID-19 positive patients, nucleocapsid protein was selected as a target antigen. We then developed an automated antibody capture-based workflow coupled to targeted high-field asymmetric waveform ion mobility spectrometry (FAIMS) - parallel reaction monitoring (PRM) assay on an Orbitrap Exploris 480 mass spectrometer. An ensemble machine learning-based model for determining COVID-19 positive samples was developed using fragment ion intensities from the PRM data.FindingsThe optimized targeted assay, which was used to analyze 88 positive and 88 negative nasopharyngeal swab samples for validation, resulted in 98% (95% CI = 0.922–0.997) (86/88) sensitivity and 100% (95% CI = 0.958–1.000) (88/88) specificity using RT-PCR-based molecular testing as the reference method.InterpretationOur results demonstrate that direct detection of infectious agents from clinical samples by tandem mass spectrometry-based assays have potential to be deployed as diagnostic assays in clinical laboratories, which has hitherto been limited to analysis of pure microbial cultures.

Laryngotracheal aspiration test reduce the false negative rate in patients with suspected SARS-COV-2 pneumonia despite a negative nasopharyngeal swab

BackgroundIn the emergency department (ED) definitive diagnosis of SARS-COV-2 pneumonia is challenging as nasopharyngeal swab (NPS) can give false negative results. Strategies to reduce false negative rate of NPS have limitations. Serial NPSs (24–48 h from one another) are time-consuming, sputum can not be collected in the majority of patients, and bronchoalveolar lavage (BAL), the most sensitive test, requires specific expertise.Laryngotracheal aspiration (LTA) is easy to perform and showed a similar accuracy to BAL for diagnosis of other pulmonary diseases, however it was not studied to diagnose SARS-COV-2 pneumonia. ObjectiveAn observational cross-sectional study was performed to evaluate the negative predictive value of LTA in patients with suspected SARS-COV-2 pneumonia despite a negative NPS. MethodsIn the EDs of two university hospitals, consecutive patients with suspected SARS-COV-2 pneumonia despite a negative NPS underwent LTA performed with a nasotracheal tube connected to a vacuum system. Final diagnosis based on all respiratory specimen tests (NPS, LTA and BAL) and hospital data was established by two reviewers and in case of discordance by a third reviewer. Results117 patients were enrolled. LTA was feasible in all patients and no patients experienced adverse events. Fifteen (12.7%) patients were diagnosed with community-acquired SARS-COV-2 pneumonia: 13 LTA positive and only 2 (1.7%) LTA negative. The negative predictive value of NPS and LTA was 87.3% (79.9% – 92.7%) and 98.1% (93.3%99.8%) respectively. ConclusionsLTA resulted feasible, safe and reduced false negative rate in patients with suspected SARS-COV-2 pneumonia despite a negative NPS.

Exploring the Impact of Restricted Partners' Visiting Policies on Non-Infected Mothers' Mental Health and Breastfeeding Rates during the COVID-19 Pandemic.

Changes in perinatal care occurring during the coronavirus disease 2019 (COVID-19) pandemic may negatively affect mothers’ mental health and breastfeeding. This study, performed between April and May 2020, aimed to investigate the effect of restricted partners’ visiting policies on non-infected mother’s anxiety symptoms, the perceived postpartum support, and the breastfeeding outcomes at discharge. A cross-sectional study was conducted in a neonatal tertiary referral center in northern Italy during Italy’s lockdown. We enrolled mothers with a negative nasopharyngeal swab for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), adequate oral and written comprehension of the Italian language, and absence of underlying maternal or neonatal clinical conditions. Maternal anxiety levels were assessed through the State-Trait Anxiety Inventory-Form Y (STAI-Y). Maternal perception of staff’s support was evaluated by the Nurse Parent Support Tool (NPST). A STATE-A (concurrent emotional state after a specific situation) score ≥ 40 was considered indicative of clinically significant symptoms of anxiety. A total of 109 mothers completed the study. Mean STATE-A score was ≥40 in 42% of mothers, and median NPST score was 4.23. Mothers separated from their partner had a mean STATE-A score ≥ 40 in a higher percentage of cases than those who were not (51% vs. 30%, p = 0.03) and a lower perception of caregiver support. A NPST score ≤4.23, partner ‘s absence during the hospital stay and primiparity were independently associated with a STATE-A score ≥ 40. Breastfeeding rates at discharge were not influenced by maternal anxiety levels and partner’s restricted policies. Instead, they were influenced by mode of delivery, a well-known risk factor, and pre-pandemic intention to breastfeed. Our study demonstrates the positive impact of a partner’s presence on maternal mental health and perception of caregiver support.

Clinical Differences between COVID-19 and a COVID-Like Syndrome.

COVID-19 is an infection due to SARS-CoV-2; this virus has been identified as the cause of the present pandemic. Several typical characteristics are present in this infection, in particular pneumonia with possible lung failure, but atypical clinical presentations are being described daily by physicians around the world. Ground-glass opacities with pneumonia are the most common and dangerous presentations of the COVID-19 disease, and they are usually associated with positive nasopharyngeal swab (NPS) tests with detectable SARS-CoV-2 viral RNA. Compared to the general population, hospital workers have been at a greater risk of infection ever since the first patients were hospitalized. However, hospital workers have also been reported as having COVID-like symptoms despite repeated negative swab tests but having tested positive for SARS-CoV-2 antibodies with serological tests. We can postulate that a COVID-like syndrome is possible, in particular in hospital workers, that is characterized by symptoms similar to those of COVID-19, but with repeated negative nasopharyngeal swabs. These repeated negative NSPs make the difference in daily clinical management with people that experienced a single false negative nasopharyngeal swab; furthermore, a clear clinical differentiation of these situations is still lacking in the literature. For this reason, here, we report our main findings from a cohort of patients with a COVID-like syndrome compared to a similar group affected by typical COVID-19.

Clinical, Biochemical and Molecular Evaluations of Ivermectin Mucoadhesive Nanosuspension Nasal Spray in Reducing Upper Respiratory Symptoms of Mild COVID-19.

BackgroundIvermectin is an FDA-approved broad-spectrum anti-parasitic agent that has been shown to inhibit SARS-CoV-2 replication in vitro.ObjectiveWe aimed to assess the therapeutic efficacy of ivermectin mucoadhesive nanosuspension intranasal spray in treatment of patients with mild COVID-19.MethodsThis clinical trial included 114 patients diagnosed as mild COVID-19. Patients were divided randomly into two age and sex-matched groups; group A comprising 57 patients received ivermectin nanosuspension nasal spray twice daily plus the Egyptian protocol of treatment for mild COVID-19 and group B comprising 57 patients received the Egyptian protocol for mild COVID-19 only. Evaluation of the patients was performed depending on improvement of presenting manifestations, negativity of two consecutive pharyngeal swabs for the COVID-19 nucleic acid via rRT-PCR and assessments of hematological and biochemical parameters in the form of complete blood counts, C-reactive protein, serum ferritin and d-dimer which were performed at presentation and 7 days later.ResultsOf the included patients confirmed with mild COVID-19, 82 were males (71.9%) and 32 females (28.1%) with mean age 45.1 ± 18.9. In group A, 54 patients (94.7%) achieved 2 consecutive negative PCR nasopharyngeal swabs in comparison to 43 patients (75.4%) in group B with P = 0.004. The durations of fever, cough, dyspnea and anosmia were significantly shorter in group A than group B, without significant difference regarding the duration of gastrointestinal symptoms. Duration taken for nasopharyngeal swab to be negative was significantly shorter in group A than in group B (8.3± 2.8 days versus 12.9 ± 4.3 days; P = 0.0001).ConclusionLocal use of ivermectin mucoadhesive nanosuspension nasal spray is safe and effective in treatment of patients with mild COVID-19 with rapid viral clearance and shortening the anosmia duration.Clinicaltrials.gov IdentifierNCT04716569; https://clinicaltrials.gov/ct2/show/NCT04716569.

Sensitive Immunodetection of Severe Acute Respiratory Syndrome Coronavirus 2 Variants of Concern 501Y.V2 and 501Y.V1.

Emerging SARS-CoV-2 variants potentially influence the effectiveness of existing laboratory diagnostics. In this study we determined whether the British (20I/501Y.V1) and South-African (20H/501Y.V2) SARS-CoV-2 variants-of-concern (VOC) are detected by an in-house S1-based antigen-detection assay. Analysis was performed in spiked pools of qRT-PCR negative nasopharyngeal swab specimens. The assay, composed of a combination of four monoclonal antibodies, allowed sensitive detection of both the wild-type and the analyzed VOCs, despite the accumulation of several mutations in the variants’ S1 region. We suggest that the combination of four monoclonal antibodies, targeting distinct epitopes, maintained both the specificity and the universality of the assay.

One-Year Update on Salivary Diagnostic of COVID-19.

Background: Coronavirus disease 2019 (COVID-19) is a global health problem, which is challenging healthcare worldwide. In this critical review, we discussed the advantages and limitations in the implementation of salivary diagnostic platforms of COVID-19. The diagnostic test of COVID-19 by invasive nasopharyngeal collection is uncomfortable for patients and requires specialized training of healthcare professionals in order to obtain an appropriate collection of samples. Additionally, these professionals are in close contact with infected patients or suspected cases of COVID-19, leading to an increased contamination risk for frontline healthcare workers. Although there is a colossal demand for novel diagnostic platforms with non-invasive and self-collection samples of COVID-19, the implementation of the salivary platforms has not been implemented for extensive scale testing. Up to date, several cross-section and clinical trial studies published in the last 12 months support the potential of detecting SARS-CoV-2 RNA in saliva as a biomarker for COVID-19, providing a self-collection, non-invasive, safe, and comfortable procedure. Therefore, the salivary diagnosis is suitable to protect healthcare professionals and other frontline workers and may encourage patients to get tested due to its advantages over the current invasive methods. The detection of SARS-CoV-2 in saliva was substantial also in patients with a negative nasopharyngeal swab, indicating the presence of false negative results. Furthermore, we expect that salivary diagnostic devices for COVID-19 will continue to be used with austerity without excluding traditional gold standard specimens to detect SARS-CoV-2.

A Generic, Scalable, and Rapid Time-Resolved Förster Resonance Energy Transfer-Based Assay for Antigen Detection-SARS-CoV-2 as a Proof of Concept.

ABSTRACTThe ongoing coronavirus disease 2019 (COVID-19) pandemic has seen an unprecedented increase in the demand for rapid and reliable diagnostic tools, leaving many laboratories scrambling for resources. We present a fast and simple assay principle for antigen detection and demonstrate its functionality by detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in nasopharyngeal swabs. The method is based on the detection of SARS-CoV-2 nucleoprotein (NP) and S protein (SP) via time-resolved Förster resonance energy transfer (TR-FRET) with donor- and acceptor-labeled polyclonal anti-NP and -SP antibodies. Using recombinant proteins and cell culture-grown SARS-CoV-2, the limits of detection were established as 25 pg of NP or 20 infectious units (IU) and 875 pg of SP or 625 IU. Testing reverse transcription-PCR (RT-PCR)-positive (n = 48, with cycle threshold [CT] values from 11 to 30) or -negative (n = 96) nasopharyngeal swabs demonstrated that the assay yielded positive results for all samples with CT values of <25 and for a single RT-PCR-negative sample. Virus isolation from the RT-PCR-positive nasopharyngeal swabs showed a strong association between the presence of infectious virus and a positive antigen test result. The NP-based assay showed 97.4% (37/38) sensitivity and 100% (10/10) specificity in comparison with virus isolation and 77.1% (37/48) sensitivity and 99.0% (95/96) specificity in comparison with SARS-CoV-2 RT-PCR. The assay is performed in a buffer that neutralizes SARS-CoV-2 infectivity, and the assay is relatively simple to set up as an “in-house” test. Here, SARS-CoV-2 served as the model pathogen, but the assay principle is applicable to other viral infections, and the test format could easily be adapted to high-throughput testing.

Performance characteristics of the Abbott Alinity m SARS-CoV-2 assay.

Mass molecular diagnostic testing for the SARS-CoV-2 pandemic has drawn on laboratory developed tests, commercial assays, and fully-automated platforms to accommodate widespread demand. The Alinity m instrument by Abbott is capable of detecting several clinically relevant pathogens and has recently received FDA emergency use authorization for SARS-CoV-2 molecular testing. The Alinity m performs automatic sample preparation, RT-PCR assembly, amplification, detection, and result calculation in under two hours. Here, we validate the performance characteristics of the Alinity m SARS-CoV-2 assay in comparison with the Roche cobas 6800 and Hologic Panther Fusion platforms. Across 178 positive and 195 negative nasopharyngeal swab specimens (CT range 14.30–38.84), the Alinity m detected one additional positive specimen that was found to be negative on the Roche cobas 6800 (PPA 100%, NPA 99.5%). Across a separate set of 30 positive and 174 negative nasopharyngeal swab specimens (CT range 14.1–38.5), the Alinity m had 100% positive and negative agreement with the Hologic Panther Fusion. Using SeraCare SARS-CoV-2 RNA standards, the assay limit of detection was verified to be two-fold more sensitive than the parameters stated by the SARS-CoV-2 AMP kit package insert, at 50 virus copies/mL. Assay specificity was 100% over 20 specimens positive for other respiratory viruses and intraday precision was 100% concordant with <2% CV. These data illst u illustrate the Abbott Alinity m system's high concordance with reference assays and analyti high analytical for SARS-CoV-2 molecular detection.

Survival in adult pneumonia inpatients fulfilling suspected COVID-19 criteria and baseline negative RT-qPCR

ObjectivesThe objective of this study was to evaluate the survival experience of suspicion COVID-19 hospitalized patients with pneumonia and negative baseline reverse-transcription quantitative polymerase chain reaction (RT-qPCR) test results. Study designWe conducted a nationwide retrospective cohort study in Mexico. MethodsAdult pneumonia inpatients fulfilling suspected COVID-19 criteria, and hospital entry from March to August 2020, were enrolled. The Kaplan–Meier method was to use to compare survival estimates among patients with negative RT-qPCR nasopharyngeal or oropharyngeal swabs and those with a baseline positive test. ResultsData from 64,624 individuals fulfilling suspected COVID-19 criteria were analyzed and 1.6% of them had negative RT-qPCR tests. The overall mortality rate was higher among laboratory-positive patients (48.5% vs. 34.2%, P < 0.001) and, at any given threshold, the survival estimates were higher among RT-qPCR–negative pneumonia inpatients. ConclusionsThe pathogenic mechanism of COVID-19 remains poorly understood and suspected cases with pneumonia and negative laboratory results represent a major challenge for healthcare systems. Our findings suggest that RT-qPCR–negative inpatients may have an improved disease prognosis, but the in-hospital mortality was still high among them. However, further research is needed to clarify the clinical and epidemiological implications of our results.

COVID-19 Infection: Viral Clearance and Antibody Response in Dialysis Patients and Renal Transplant Recipients

Background/Aims: The coronavirus disease 2019 (CO­VID-19) pandemic is the major current health emergency worldwide, adding a significant burden also to the community of nephrologists for the management of their patients. Here, we analyzed the impact of COVID-19 infection in renal patients to assess the time to viral clearance, together with the production and persistence of IgG and IgM antibody response, in consideration of the altered immune capacity of this fragile population. Methods: Viral clearance and antibody kinetics were investigated in 49 renal patients recovered from COVID-19 infection: 7 of them with chronic decompensated renal failure, 31 under dialysis treatment, and 11 kidney transplant recipients. Results: The time span between the diagnosis of infection and recovery based on laboratory testing (2 negative nasopharyngeal swabs in consecutive days) was 31.7 ± 13.3 days. Three new positive cases were detected from 8 to 13 days following recovery. At the first serological determination after swab negativization, all the patients developed IgG and IgM antibodies. The semiquantitative analysis showed a progressive increase in IgG and a slow reduction in IgM. Discussion/Conclusion: In subjects with decompensated chronic kidney disease, under dialysis and in transplant recipients, viral clearance is lengthened compared to the general population. However, in spite of their common status of immunodepression, all of them were able to produce specific antibodies. These data might provide useful insights for monitoring and planning health-care activities in the weak category of patients with compromised renal function recovered from COVID-19.

No Efficacy of the Combination of Lopinavir/Ritonavir Plus Hydroxychloroquine Versus Standard of Care in Patients Hospitalized With COVID-19: A Non-Randomized Comparison.

Objectives: No specific treatment has been approved for COVID-19. Lopinavir/ritonavir (LPV/r) and hydroxychloroquine (HCQ) have been used with poor results, and a trial showed advantages of combined antiviral therapy vs. single antivirals. The aim of the study was to assess the effectiveness of the combination of antivirals (LPV/r and HCQ) or their single use in COVID-19 hospitalized patients vs. standard of care (SoC). Methods: Patients ≥18 years with SARS-CoV-2 infection, defined as positive RT-PCR from nasal/oropharyngeal (NP/OP) swab or positive serology, admitted at L. Spallanzani Institute (Italy) were included. Primary endpoint: time to invasive ventilation/death. Secondary endpoint: time to two consecutive negative SARS-CoV-2 PCRs in NP/OP swabs. In order to control for measured confounders, a marginal Cox regression model with inverse probability weights was used. Results: A total of 590 patients were included in the analysis: 36.3% female, 64 years (IQR 51–76), and 91% with pneumonia. Cumulative probability of invasive ventilation/death at 14 days was 21.2% (95% CI 17.6, 24.7), without difference between SOC, LPV/r, hydroxychloroquine, HCQ + LPV/r, and SoC. The risk of invasive ventilation/death in the groups appeared to vary by baseline ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2). Overall cumulative probability of confirmed negative nasopharyngeal swabs at 14 days was 44.4% (95% CI 38.9, 49.9), without difference between groups. Conclusion: In this retrospective analysis, we found no difference in the rate of invasive ventilation/death or viral shedding by different strategies, as in randomized trials performed to date. Moreover, even the combination HCQ + LPV/r did not show advantages vs. SoC.

Favipiravir in the treatment of patients with SARS-CoV-2 RNA recurrent positive after discharge: A multicenter, open-label, randomized trial

BackgroundThe clinical characteristics and treatment of patients who tested positive for COVID-19 after recovery remained elusive. Effective antiviral therapy is important for tackling these patients. We assessed the efficacy and safety of favipiravir for treating these patients. MethodsThis is a multicenter, open-label, randomized controlled trial in SARS-CoV-2 RNA re-positive patients. Patients were randomly assigned in a 2:1 ratio to receive either favipiravir, in addition to standard care, or standard care alone. The primary outcome was time to achieve a consecutive twice (at intervals of more than 24 h) negative RT-PCR result for SARS-CoV-2 RNA in nasopharyngeal swab and sputum sample. ResultsBetween March 27 and May 9, 2020, 55 patients underwent randomization; 36 were assigned to the favipiravir group and 19 were assigned to the control group. Favipiravir group had a significantly shorter time from start of study treatment to negative nasopharyngeal swab and sputum than control group (median 17 vs. 26 days); hazard ratio 2.1 (95% CI [1.1–4.0], p = 0.038). The proportion of virus shedding in favipiravir group was higher than control group (80.6% [29/36] vs. 52.6% [10/19], p = 0.030, respectively). C-reactive protein decreased significantly after treatment in the favipiravir group (p = 0.016). The adverse events were generally mild and self-limiting. ConclusionFavipiravir was safe and superior to control in shortening the duration of viral shedding in SARS-CoV-2 RNA recurrent positive after discharge. However, a larger scale and randomized, double-blind, placebo-controlled trial is required to confirm our conclusion.

V5 Preoperative nasopharyngeal swab testing and postoperative pulmonary complications in patients undergoing elective surgery during the SARS-CoV-2 pandemic

BackgroundSurgical services are preparing to scale up in areas affected by COVID-19. This study aimed to evaluate the association between preoperative SARS-CoV-2 testing and postoperative pulmonary complications in patients undergoing elective cancer surgery.MethodsThis international cohort study included adult patients undergoing elective surgery for cancer in areas affected by SARS-CoV-2 up to 19 April 2020. Patients suspected of SARS-CoV-2 infection before operation were excluded. The primary outcome measure was postoperative pulmonary complications at 30 days after surgery. Preoperative testing strategies were adjusted for confounding using mixed-effects models.ResultsOf 8784 patients (432 hospitals, 53 countries), 2303 patients (26.2 per cent) underwent preoperative testing: 1458 (16.6 per cent) had a swab test, 521 (5.9 per cent) CT only, and 324 (3.7 per cent) swab and CT. Pulmonary complications occurred in 3.9 per cent, whereas SARS-CoV-2 infection was confirmed in 2.6 per cent. After risk adjustment, having at least one negative preoperative nasopharyngeal swab test (adjusted odds ratio 0.68, 95 per cent confidence interval 0.68 to 0.98; P = 0.040) was associated with a lower rate of pulmonary complications. Swab testing was beneficial before major surgery and in areas with a high 14-day SARS-CoV-2 case notification rate, but not before minor surgery or in low-risk areas. To prevent one pulmonary complication, the number needed to swab test before major or minor surgery was 18 and 48 respectively in high-risk areas, and 73 and 387 in low-risk areas.ConclusionPreoperative nasopharyngeal swab testing was beneficial before major surgery and in high SARS-CoV-2 risk areas. There was no proven benefit of swab testing before minor surgery in low-risk areas.

Bronchoalveolar lavage in suspected COVID-19 cases with a negative nasopharyngeal swab: a retrospective cross-sectional study in a high-impact Northern Italy area.

COVID-19 diagnosis relies on molecular testing for SARS-CoV-2 via nasopharyngeal swab in the presence of suggestive clinical, radiological and laboratory findings. Since bronchoalveolar lavage liquid (BAL) collected during fibrobronchoscopy may increase test sensitivity compared to nasopharyngeal swabs, it was performed during the 2020 pandemic in clinically or radiologically suspected cases. Our aim was to determine whether clinical features, chest computed tomography (CT) findings or laboratory tests may predict patients testing positive for SARS-CoV-2 at BAL after a negative nasopharyngeal swab. We performed a retrospective cross-sectional study with multivariable analysis of suspected patients who were tested for SARS-CoV-2 at BAL after at least one negative nasopharyngeal swab. Univariable logistic regression for odds ratio and multivariate models was calculated to determine clinical, radiological and laboratory predictors. 32/198 (16%) patients had BAL positive for SARS-CoV-2, while 65/198 tested positive for other pathogens at BAL. Of the 32 patients positive for COVID, 4 had a coinfection at BAL, being thus positive both for COVID as well as for another pathogen while the remaining 105 patients were negative for COVID and other pathogens at BAL. COVID-19 patients had more often highly suggestive CT findings, higher number of involved lobes, more often ground glass opacity of more than 50% of lung parenchyma, and less frequently other radiologically suspected infections. At multivariate model, temperature also predicted BAL positivity. The procedure was well tolerated—with only one desaturation episode—while no healthcare worker was infected. In conclusion, when nasopharyngeal swabs are negative but there is clinical or imaging suspicion of COVID-19, BAL represents a complementary diagnostic tool, particularly in conjunction with suggestive/more extensive lung involvement at CT scan. The procedure did not carry increased risks for patients nor for operators, while allowing to free hospital resources, avoiding unnecessary isolations.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11739-021-02714-y.

Comparative Evaluation of Tears and Nasopharyngeal Swab for SARS-CoV-2 in COVID-19 Dedicated Intensive Care Unit Patients

ABSTRACT Purpose: To compare the cycle threshold (Ct) values of tears and nasopharyngeal (NP) swab in severe COVID-19 ICU patients with positive NP swabs. Procedure: A cross-sectional study for the detection of SARS-CoV-2 by real-time RT-PCR on simultaneously collected NP swabs and tears was performed. Detailed demographic profile, including comorbidities, ocular, and systemic features were analyzed. Results: In the 78 cases, the mean tear positivity was 26.92% (21/78), 2 tear samples being positive despite a negative NP swab. The mean Ct value of tears and NP were 28.17 ± 4.76 and 23.71 ± 6.19, respectively (p= .003). None of the cases had ocular findings or relationship between tear positivity and comorbidity. Conclusions: The viral load of tears is less than the NP secretions with the possibility of prolonged shedding in tears. Tears act as an additional source of contact transmission in ICU that can possibly be decreased by frequent hand hygiene by the patient. Abbreviations: SARS-CoV-2: Severe acute respiratory syndrome coronavirus; RT-PCR: Real-time Reverse transcriptase–polymerase chain reaction; COVID-19: Corona virus disease 2019; ICU: Intensive care unit; RdRp: RNA-dependent RNA polymerase; ORF 1b: Open reading frame 1b; AIIR: Airborne infection isolation room; HCW: Health care workers; VTM: viral transport media; NP: Nasopharyngeal swab; PPE: Personal protective equipment.

Moderate forms of COVID-19 among healthcare workers in a Belgian hospital and their immune response

ABSTRACT Introduction Healthcare professionals have been treating patients with COVID-19 since the pandemic started in early 2020 while also trying to limit disease spread among their coworkers and communities. This study aimed to identify and follow potentially infected healthcare workers in one hospital in order to develop an epidemiological baseline for COVID-19 infection and spread rates in this population. Materials and methods This prospective study was conducted between 1 April and 30 June 2020 at a single Belgian hospital. Healthcare workers with symptoms consistent with COVID-19 were included. Participants underwent testing for SARS-CoV-2 infection by nasopharyngeal (NP) swab and analysis of blood samples for antibody response at different timepoints (day 0, 7, 14 and day 30 or 60). Patient exposures, symptoms, and disease progression were collected. Results Of a total of 150 healthcare workers with symptoms compatible with SARS-CoV-2 infection, 31% (47) tested positive for the virus by NP swab. Of the 47 participants with positive NP swabs, 66% also had positive IgG serology. Of the 99 participants with negative NP swabs who underwent blood sample collection, 5% had positive IgG serology results. Of the 29 participants who presented with at least 3 major symptoms, 15 (52%) had positive NP swabs and 14 (48%) had positive serology. Conclusions This study demonstrates that evidence of symptoms, even when major, is a poor predictor for SARS-CoV-2 positivity in health care workers and raises the question of the best way to efficiently screen this population especially during the upcoming flu period.

A Case of Severe COVID-19 Pneumonia Diagnosed in Bronchoscopy With Negative Repeated Nasopharyngeal Swabs

Coronavirus disease 2019 (COVID-19) is a worldwide pandemic that had emerged in China since December 2019. The disease affects all age groups, with clinical manifestations in the spectrum from asymptomatic to rapidly lethal multi-organ failure, mainly involving the respiratory system. Diagnosis is confirmed mainly by a positive real-time polymerase chain reaction (PCR) nasopharyngeal swab. It is highly recommended to avoid performing invasive procedures in COVID-19 subjects to prevent the potential for dissemination of the pathogen. Treatment consists in particular of respiratory support and symptom relief. Dexamethasone is widely used with encouraging response. There were no cases in the literature that were diagnosed with positive reverse transcription-polymerase chain reaction (RT-PCR) testing only from fluid of involved organs, while repeated nasopharyngeal swabs returned negative for COVID-19. We here describe a case of COVID-19 that presented with moderate-severe pulmonary involvement, diagnosed by RT-PCR testing from broncho-alveolar lavage, while several nasopharyngeal swabs were consistently negative. The patient experienced no improvement under wide-spectrum antibiotics administered initially, and greatly improved after receiving systemic corticosteroids. One can realize from our case that COVID-19 could not be ruled out upon repeated negative RT-PCR nasopharyngeal swabs, and in subjects with highly suspected COVID-19, it is justified to perform invasive procedures, but still using maximal protective measures. J Med Cases. 2021;12(6):217-219 doi: https://doi.org/10.14740/jmc3679