Complications of Nasopharyngeal Swabs and Safe Procedures for COVID-19 Testing Based on Anatomical Knowledge

Anterior nasal swabs compared to nasopharyngeal swabs for detection of respiratory viruses in children

Respiratory viral testing often uses invasive nasopharyngeal (NP) swabs, which can be painful and require trained personnel. Anterior nasal swabs (NS) are less invasive and can be self-collected. The sensitivity of NS compared to NP specimens for detecting multiple respiratory viruses in children are not well described. Hospitalized children in Kansas City, MO, from January 2023 to February 2024, who had NP specimens obtained for standard of care multiplex respiratory viral testing in the previous 72 h, were enrolled. NS specimens were collected and tested alongside salvaged NP specimens for adenovirus, seasonal coronaviruses, human metapneumovirus, respiratory syncytial virus, influenza, rhinovirus/enterovirus, SARS-CoV-2, and parainfluenza viruses using multiplex molecular testing. Concordance, sensitivity, and specificity of NS compared to NP specimens were assessed. A total of 147 paired NP/NS specimens were analyzed. Overall, 114 (77.6 %) NP/NS pairs were concordant, including 86 (58.5 %) virus-positive and 28 (19.1 %) virus-negative pairs. NS sensitivity was 84.3 % compared to NP, increasing to 95.7 % when collected within 24 h of NP specimens. Sensitivity for seasonal coronavirus was poor (36.4 %), but was over 75 % for other viruses, and 100 % for adenovirus, influenza, parainfluenza, RSV, and SARS-CoV-2 within 24 h of NP specimens. Virus cycle threshold counts were similar among paired specimens. NS specimens showed good concordance with NP specimens and high sensitivity for most viruses, except seasonal coronavirus. NS testing may enable respiratory virus monitoring outside medical settings.

Saline gargle collection method is comparable to nasopharyngeal/oropharyngeal swabbing for the molecular detection and sequencing of SARS-CoV-2 in Botswana

The coronavirus disease 2019 pandemic has highlighted the importance and challenges of the sample collection component of the diagnostic cycle. Although combined nasopharyngeal and oropharyngeal swabs (NOS) have historically been the gold standard of sampling, the saline gargle (SG) sampling method has been evaluated and implemented in multiple jurisdictions for respiratory pathogen detection. It has proven to be user-acceptable to patients, simple to collect, and highly sensitive to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection by molecular methods when compared to swabs. We performed a prospective cross-sectional study to evaluate the SG collection method against the NOS collection method for molecular detection and next-generation sequencing (NGS) of SARS-CoV-2 in Botswana. Paired SG and NOS samples were collected and underwent nucleic acid extraction prior to molecular detection. The SG had an overall sensitivity of 81.3% (95% CI: 68.8%%-96.0%), while the NOS had an overall sensitivity of 96.9% (95% CI: 84.3-99.4). Paired samples with a mean crossing threshold value of <35 also underwent NGS. SG specimens had a median genome coverage of 94.7% (interquartile range [IQR] 87.0%-99.2%) and NOS specimens had a median genome coverage of 99.6% (IQR 90.0%-99.6%). Bioinformatics analysis showed the 15 successfully matched pairs belong to clades BA.1 and BA.2 indicative of the Omicron variant. Further analysis at the nucleotide level showed a mean similarity of 99.998% ± 0.00465% between NOS and SG. This method has the potential to overcome the challenges that come with swab-based sampling for SARS-CoV-2 testing and may be an alternative in testing for other viral pathogens.

IMPORTANCE

During the coronavirus disease 2019 (COVID-19) pandemic, a major challenge has been inadequate sampling for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pediatric patients posed additional challenges with sample collection, and they and others are also at risk of rare complications from swab collection. Saline gargle (SG) sampling method has been evaluated and introduced as an alternative to swab collection in several jurisdictions. Our study affirms the acceptable performance of the saline gargle method for the molecular detection of SARS-CoV-2 and also establishes that SG samples do not pose an obstacle for genomic sequencing of SARS-CoV-2. The SG method may be a reliable alternative for SARS-CoV-2 detection and next-generation sequencing, facilitating COVID-19 surveillance efforts in resource-constraint settings.

Point-Of-Need One-Pot Multiplexed RT-LAMP Test For Detecting Three Common Respiratory Viruses In Saliva

Respiratory viral infections pose a significant global public health challenge, partly due to the difficulty in rapidly and accurately distinguishing between viruses with similar symptoms at the point of care, hindering timely and appropriate treatment and limiting effective infection control and prevention efforts. Here, we developed a multiplexed, non- invasive saliva-based, reverse transcription loop-mediated isothermal amplification (RT- LAMP) test that enables the simultaneous detection of three of the most common respiratory infections, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Influenza (Flu), and respiratory syncytial virus (RSV), in a single reaction via specific probes and monitored in real-time by a machine-learning-enabled compact analyzer. Our results demonstrate that the multiplexed assay can effectively detect three target RNAs with high accuracy. Further, testing with spiked saliva samples showed strong agreement with reverse transcription polymerase chain reaction (RT-PCR) assay, with area under the curve (AUC) values of 0.82, 0.93, and 0.96 for RSV, Influenza, and SARS-CoV-2, respectively. By enabling the rapid detection of respiratory infections from easily collected saliva samples at the point of care, the device presented here offers a practical and efficient tool for improving outcomes and helping prevent the spread of contagious diseases.

Significance

This research presents an innovative approach to respiratory infection diagnostics by combining a one-pot isothermal molecular test with machine learning-based analysis to simultaneously detect SARS-CoV-2, Influenza, and RSV in saliva samples. The battery- powered portable analyzer features novel machine-learning-assisted fluorescence detection for multiplexed reporter quantification, eliminating the need for traditional filter- based optical components and enabling adaptation to new targets without hardware changes. The test demonstrates high accuracy in detecting single and co-infections in spiked saliva samples, providing a rapid, cost-effective point-of-need solution. This tool can expand testing access, improve patient outcomes, and support more effective disease control, particularly in resource-limited or decentralized healthcare settings.

Pituitary surgery and COVID

An effect of the COVID-19 pandemic was the disruption of healthcare systems, especially surgical services provided to the community. Pituitary surgery was especially impacted, given the majority of cases were deemed non-urgent with very few exceptions, and the high risk of viral transmission conferred by the endoscopic endonasal transsphenoidal approach. Patients suffering from pituitary lesions with resultant endocrinopathy or visual symptoms saw their treatment delayed or altered, which had implications on their outcomes and care. This disruption extended to surgical training and the usual functioning of academic units, necessitating changes to curricula and implementation of novel methods of progressing surgical education. This review will explore the effect of the COVID pandemic on pituitary surgery, the experiences of various surgeons as well as the adaptations implemented on the frontlines. The lessons learned from the experience of the pandemic may assist specialists in gleaning insights regarding the care of patients in the future.

Accuracy of point-of-care SARS-CoV-2 detection using buccal swabs in pediatric emergency departments

To optimize the identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected children, specimen collection and testing method are crucial considerations. Ideally, specimen collection is easy and causes minimal discomfort, and the laboratory approach is simple, accurate, and rapid. In this prospective cohort study we evaluated the accuracy of a point-of care nucleic acid device using caregiver/patient self-collected buccal swabs. Participants were recruited in 14 Canadian tertiary care pediatric emergency departments. Children <18 years of age deemed to require SARS-CoV-2 testing were eligible. Caregivers or the patient-collected buccal swabs which were tested on the ABBOTT ID NOW. The reference standard was nasopharyngeal swab specimens collected by a healthcare provider tested via laboratory reverse transcription PCR (RT-PCR). We enrolled 2,640 study participants and 14.4% (381/2,640) were SARS-CoV-2 RT-PCR-positive. Eight percent (223/2,640) and 85.0% (2,244/2,640) were concordant test-positive and concordant test-negative, respectively. Sensitivity and specificity of the investigational approach were 58.5% [95% confidence interval (CI): 53.4, 63.5] and 99.3% (95% CI: 98.9, 99.6), respectively. Cycle threshold values were lower among concordant [median 17 (15, 21)] relative to discordant [median 30 (22, 35)] swabs (P < 0.001). Sensitivity was greatest among children <4 years of age, when caregivers performed the swabs, among unvaccinated children, and those with shorter symptom duration. Across multiple pain measures, less pain was associated with buccal swab testing. Although accuracy of the buccal swab point-of-care SARS-CoV-2 test was good and negative agreement was excellent, sensitivity was only 58.5%. Concordance was greater among those with higher viral loads, and the approach involving buccal swabs was less painful.IMPORTANCETo optimize the identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected children, specimen collection and testing method are crucial considerations. Ideally, specimen collection is easy and causes minimal discomfort, and laboratory approach is simple, accurate, and rapid. We evaluated the accuracy and pain associated with buccal swab specimen collection by caregivers or children themselves who were tested using a point-of-care isothermal nucleic acid amplification SARS-CoV-2 test. This novel approach was compared to nasopharyngeal swab specimens tested using laboratory-based PCR tests. While negative agreement was excellent, positive percent agreement was less than 60%. Concordance was greater among those with higher viral loads, and thus, sensitivity is excellent when transmissibility is more likely to occur. Importantly, the approach involving buccal swabs was significantly less painful, and thus, children and their caregivers are more likely to agree to testing using such an approach.CLINICAL TRIALSRegistered at ClinicalTrials.gov (NCT05040763).

Our Experience With Intractable Epistaxis After COVID-19 Nasopharyngeal Swab

INTRODUCTION

Although a COVID-19 nasopharyngeal swab is a safe procedure routinely performed by healthcare providers, it can lead to complications that can be life-threatening. We present seven cases of intractable epistaxis following a nasopharyngeal swab that required sphenopalatine artery ligation. We aim to shed light on this life-threatening condition, emphasizing the importance of recognizing and mitigating such complications.

MATERIALS AND METHODS

This retrospective chart review involved cases of intractable epistaxis following a COVID-19 swab from January 2020 to June 2022. The patient's charts were reviewed for the location of the epistaxis and different intranasal and extranasal factors that could have led to it.

RESULTS

Seven cases had intractable epistaxis following a nasopharyngeal COVID-19 swab. Six of the seven cases had a deviated nasal septum, and one case had an enlarged inferior turbinate. All patients had bleeding from the ipsilateral nasal structural abnormality. All patients underwent successful sphenopalatine artery ligation.

CONCLUSION

Our study highlights the significance of recognizing the potential risk of intractable epistaxis post-COVID-19 swabs and emphasizes the importance of comprehensive training programs to ensure the safe and effective execution of nasopharyngeal swab procedures.

Robotic system for nasopharyngeal swab sampling based on remote center of motion mechanism

PURPOSE

In this study, a robotic system is proposed for nasopharyngeal (NP) swab sampling with high safety and efficiency. Most existing swab-sampling robots have more than six degrees of freedom (DOFs). However, not all six DOFs are necessarily required for NP swab sampling. A high number of DOFs can cause safety problems, such as collisions between the robot and patient.

METHOD

We developed a new type of robot with four DOFs for NP swab sampling that consists of a two DOFs remote center of motion (RCM) mechanism, a two DOFs insertion mechanism, and a nostril support unit. With the nostril support unit, the robot no longer needs to adjust the insertion position of the swab. The proposed robot enables the insertion orientation and depth to be adjusted according to different postures or facial shapes of the subject. For intuitive and precise remote control of the robot, a dedicated master device for the RCM and a visual feedback system were developed.

RESULT

The effectiveness of the robotic system was demonstrated by repeatability, RCM accuracy, tracking accuracy, and in vitro phantom experiments. The average tracking error between the master device and the robot was less than 2 mm. The contact force exerted on the swab prior to reaching the nasopharynx was less than 0.04 N, irrespective of the phantom's pose.

CONCLUSION

This study confirmed that the RCM-based robotic system is effective and safe for NP swab sampling while using minimal DOFs.

Nasopharyngeal Swabs in Pediatric Patients With Thrombocytopenia and Anticoagulant Use

BACKGROUND

Nasopharyngeal (NP) swabbing is a technique that is commonly used to test pediatric patients for viral infections with increased use during the coronavirus disease 2019 pandemic. Complications from NP swabbing are rare and seem to occur more frequently in patients at risk of bleeding. Little is known about institutional or individual practices and experiences with NP swab testing in pediatric patients with risk factors for bleeding.

METHODS

We conducted a survey study of pediatric hematology/oncology (PHO) attending physicians to assess practices and experiences with NP swab testing in pediatric patients with thrombocytopenia and/or on anticoagulation.

RESULTS

There were 130 total respondents (5.6%, n = 130/2327) from 6 countries. Relatively few respondents (n = 17/130, 13.1%) reported that their institution had a policy specifying a lower-level platelet cutoff for patients undergoing NP swabbing. The median platelet cutoff below which NP swabs are not performed according to existing policies is 30,000×10(9)/L (interquartile range: 20,000 to 40,000). The median cutoff based on the opinion of the respondents was 10,000 (interquartile range: 10,000 to 20,000). There were 24 episodes of epistaxis among PHO patients that were NP swabbed; many adverse events (56.5%, n = 13/23) were described as persistent, severe, and/or required intervention. Three reported cases of epistaxis with anticoagulation or antiplatelet therapy occurred in patients with concomitant thrombocytopenia. Only 1 respondent (n = 1/130, 0.7%) reported an institutional policy for limiting NP swabs in patients on anticoagulant therapy. NP (66.9%) and nares (33.1%) were the most common sources of coronavirus disease 2019 testing that were reported.

CONCLUSION

A small percentage of institutions in this survey have a policy restricting NP swabs in PHO patients. The discrepancy between lower platelet cutoffs proposed by experts and institutional policy suggests that existing policies may be too conservative. Expert guidelines are needed on this topic. Other bleeding risk factors (eg, aspirin use and von Willebrand disease) should be considered in policies and guidelines.

Scanning Electron Microscopy and EDX Spectroscopy of Commercial Swabs Used for COVID-19 Lateral Flow Testing

The chemical composition of COVID test swabs has not been examined beyond the manufacturer's datasheets. The unprecedented demand for swabs to conduct rapid lateral flow tests and nucleic acid amplification tests led to mass production, including 3D printing platforms. Manufacturing impurities could be present in the swabs and, if so, could pose a risk to human health. We used scanning electron microscopy and energy dispersive X-ray (EDX) spectroscopy to examine the ultrastructure of seven assorted brands of COVID test swabs and to identify and quantify their chemical elements. We detected eight unexpected elements, including transition metals, such as titanium and zirconium, the metalloid silicon, as well as post-transition metals aluminium and gallium, and the non-metal elements sulphur and fluorine. Some of the elements were detected as trace amounts, but for others, the amount was close to reported toxicological thresholds for inhalation routes. Experimental studies have shown that the detrimental effects of unexpected chemical elements include moderate to severe inflammatory states in the exposed epithelium as well as proliferative changes. Given the massive testing still being used in the context of the COVID pandemic, we urge caution in continuing to recommend repeated and frequent testing, particularly of healthy, non-symptomatic, individuals.

Molecular Diagnosis of COVID-19; Biosafety and Pre-analytical Recommendations

From the beginning of the COVID-19 epidemic, clinical laboratories around the world have been involved with tests for detection of SARS-CoV-2. At present, RT-PCR (real-time reverse transcription polymerase chain reaction assay) is seen as the gold standard for identifying the virus. Many factors are involved in achieving the highest accuracy in this test, including parameters related to the pre-analysis stage. Having instructions on the type of sample, how to take the sample, and its storage and transportation help control the interfering factors at this stage. Studies have shown that pre-analytical factors might be the cause of the high SARS-CoV-2 test false-negative rates. Also, the safety of personnel in molecular laboratories is of utmost importance, and it requires strict guidelines to ensure the safety of exposed individuals and prevent the virus from spreading. Since the onset of the outbreak, various instructions and guidelines have been developed in this field by the institutions and the Ministry of Health of each country; these guidelines are seriously in need of integration and operation. In this study, we try to collect all the information and research done from the beginning of this pandemic in December 2019 - August 2022 concerning biosafety and protective measures, sample types, sampling methods, container, and storage solutions, sampling equipment, and sample storage and transportation for molecular testing of SARS-CoV-2.

Brain abscess as a complication of nasopharyngeal COVID-19 swab testing: Two case reports and a literature review

INTRODUCTION AND IMPORTANCE

The nasopharyngeal swab, which has experienced a marked increase in utilization during the COVID-19 pandemic and is considered the gold standard for COVID-19 testing due to its high diagnostic accuracy and sensitivity, The procedure is generally safe and well-tolerated, with pain, discomfort, and the urge to cough or sneeze being the most common complications. Though it is occasionally associated with serious complications.

CASE PRESENTATION

we report two cases of brain abscess as a complication of nasopharyngeal COVID-19 testing. The first case was of a 47-year-old male diabetic patient with a positive medical history for immune thrombocytopenic purpura (ITP) who developed a frontal brain abscess one week after the swabbing procedure and was treated with systemic antibiotics followed by a successful functional endoscopic sinus surgery. The second case involved a hypertensive female patient in her 40s who also developed a frontal brain abscess on the same side as painful nasal COVID-19 testing. Systemic antibiotics were used to treat the patient.

CLINICAL DISCUSSION

Serious adverse events from nasopharyngeal COVID-19 testing were reported to occur rarely, with incidences ranging from 0.0012 to 0.026 %. Retained swabs, epistaxis, and CSF leakage were commonly reported complications, which were frequently associated with high-risk factors such as septal deviations, pre-existing basal skull defects, and sinus surgeries. However, brain abscess complications are considered one of the extremely rare complications, with only a few cases reported in the literature.

CONCLUSION

Appropriate approaches that depend on adequate anatomical knowledge are necessary for practitioners to perform nasopharyngeal COVID-19 testing.

Diagnostic Performance and Tolerability of Saliva and Nasopharyngeal Swab Specimens in the Detection of SARS-CoV-2 by RT-PCR

Saliva is a promising alternative for a nasopharyngeal swab (NPS) in specimen collection to detect SARS-CoV-2. We compared the diagnostic performance and tolerability of saliva collection versus NPS in a clinical setting. Paired NPS and saliva specimens were collected sequentially from participants (n = 250) at the Turku University Hospital drive-in coronavirus testing station in the spring of 2022, with Omicron BA.2 as the dominant SARS-CoV-2 variant. Discomfort and preference for the sampling method were assessed. The specimens were analyzed for SARS-CoV-2 using real-time multiplex reverse transcriptase PCR (RT-PCR) with a laboratory-developed test (LDT) and two commercial kits (PerkinElmer SARS-CoV-2 and PerkinElmer SARS-CoV-2 Plus) for several target genes. Among the 250 participants, 246 had respiratory symptoms. With LDT, SARS-CoV-2 was detected in 135 and 134 participants from NPS and saliva, respectively. Of the 250 specimens, 11 gave a discordant outcome, resulting in excellent agreement between the specimen types (Cohen's kappa coefficient of 0.911; P = 0.763). The cycle threshold (CT) values of LDT and commercial kit target genes were significantly lower from NPS than from saliva. A total of 172 (69%) participants assessed saliva sampling as more tolerable than NPS (P < 0.0001). Our findings present saliva as an applicable alternative for SARS-CoV-2 diagnostics. However, the lower CT values obtained from NPS indicate that NPS may be a slightly more sensitive specimen type. Participants preferred saliva sampling, although delivering an adequate volume of saliva was challenging for some participants. IMPORTANCE The extensive testing of SARS-CoV-2 is vital in controlling the spread of COVID-19. The reference standard for specimen collection is a nasopharyngeal swab (NPS). However, the discomfort of NPS sampling, the risk of nosocomial infections, and global material shortages have accelerated the development of alternative testing methods. Our study demonstrates that patients tolerate saliva sampling better than NPS. Of importance, although the RT-PCR qualitative test results seem to correspond between NPS and saliva, we show significantly lower CT values for NPS, compared to saliva, thus contradicting the suggested superiority of the saliva specimen over NPS in the detection of the Omicron variants of SARS-CoV-2. Future research is still required to enable individual planning for specimen collection and to determine the effects of different SARS-CoV-2 variants on the sensitivity of the saliva matrix.

Identification of microplastic fibres released from COVID-19 test swabs with Raman imaging

Background

COVID-19 pandemic is not yet over, and it has been generating lots of plastic wastes that become a big concern. To catch the virus, for example, no matter via antigen or PCR test, swab is generally used for sampling. Unfortunately, the swab tip is commonly made of plastics, and thus it can be a potential source of microplastics. This study aims to propose and optimise several Raman imaging to identify the microplastic fibres released from different COVID-19 test swabs.

Results

The results show that Raman imaging can effectively identify and visualise the microplastic fibres released from the swabs. In the meantime, on the surface of the fibres, additives such as titanium oxide particles are also captured for some brands of swabs. To increase the result certainty, scanning electron microscope (SEM) is first employed to get the morphology of the released microplastic fibres, along with Energy-dispersive X-ray spectroscopy (EDS) to confirm the presence of titanium element. Then, Raman imaging is advanced to identify and visualise the microplastics and titanium oxide particles, from different characteristic peaks in the scanning spectrum matrix. To further increase the imaging certainty, these images can be merged and cross-checked using algorithms, or the raw data from the scanning spectrum matrix can be analysed and decoded via chemometrics, such as principal component analysis (PCA). Beyond the advantages, the disadvantages of the confocal Raman imaging (affected by focal height) and algorithms (non-supervised calculation) are also discussed and intentionally corrected. In brief, the imaging analysis (particularly the combined SEM with Raman) is recommended to avoid the possible result bias that might be generated from the single spectrum analysis at a selective but random position.

Conclusions

Overall, the results indicate that Raman imaging can be a useful tool to detect microplastics. The results also send us a strong warning that, if we worry about the potential microplastics contamination, we should be cautious to select the suitable COVID-19 testing kits.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12302-023-00737-0.

Evaluation of A Novel Anterior Nasal Swab for the Detection of SARS-CoV-2

BACKGROUND

During the course of the COVID-19 pandemic, nasopharyngeal swabs, combined throat and nose swabs and saliva samples have been evaluated for SARS-CoV-2 detection using nucleic acid amplification tests (NAT). Literature on anterior nasal swabs is limited and comparative studies often group anterior nasal and mid-turbinate swabs together (Tsang et al., 2021). We investigated a novel anterior nasal swab that has been designed to standardised self-collection, maximise sample uptake and improve user comfort. We used combined throat and nose swabs and neat saliva samples as the comparators.

RESULTS

The overall positive percentage agreement between the Rhinoswab™ and the combined throat and nose swab was 95.2% at day 2 post participant recruitment and 93.3% on day 4 post participant recruitment. This was favourable to the positive percentage agreement with saliva at the same time points.

CONCLUSION

In our study the Rhinoswab™ performed equally well in comparison to a combined throat and nose swab for the laboratory detection of SARS-CoV-2 using nucleic acid amplification techniques.

Comparative Performance of Serological (IgM/IgG) and Molecular Testing (RT-PCR) of COVID-19 in Three Private Universities in Cameroon during the Pandemic

BACKGROUND

COVID-19 remains a rapidly evolving and deadly pandemic worldwide. This necessitates the continuous assessment of existing diagnostic tools for a robust, up-to-date, and cost-effective pandemic response strategy. We sought to determine the infection rate (PCR-positivity) and degree of spread (IgM/IgG) of SARS-CoV-2 in three university settings in Cameroon Method: Study volunteers were recruited from November 2020 to July 2021 among COVID-19 non-vaccinated students in three Universities from two regions of Cameroon (West and Centre). Molecular testing was performed by RT-qPCR on nasopharyngeal swabs, and IgM/IgG antibodies in plasma were detected using the Abbott Panbio IgM/IgG rapid diagnostic test (RDT) at the Virology Laboratory of CREMER/IMPM/MINRESI. The molecular and serological profiles were compared, and p < 0.05 was considered statistically significant.

RESULTS

Amongst the 291 participants enrolled (mean age 22.59 ± 10.43 years), 19.59% (57/291) were symptomatic and 80.41% (234/291) were asymptomatic. The overall COVID-19 PCR-positivity rate was 21.31% (62/291), distributed as follows: 25.25% from UdM-Bangangte, 27.27% from ISSBA-Yaounde, and 5% from IUEs/INSAM-Yaounde. Women were more affected than men (28.76% [44/153] vs. 13.04% [18/138], p < 0.0007), and had higher seropositivity rates to IgM+/IgG+ (15.69% [24/153] vs. 7.25% [10/138], p < 0.01). Participants from Bangangté, the nomadic, and the "non-contact cases" primarily presented an active infection compared to those from Yaoundé (p= 0.05, p = 0.05, and p = 0.01, respectively). Overall IgG seropositivity (IgM-/IgG+ and IgM+/IgG+) was 24.4% (71/291). A proportion of 26.92% (7/26) presenting COVID-19 IgM+/IgG- had negative PCR vs. 73.08% (19/26) with positive PCR, p < 0.0001. Furthermore, 17.65% (6/34) with COVID-19 IgM+/IgG+ had a negative PCR as compared to 82.35% with a positive PCR (28/34), p < 0.0001. Lastly, 7.22% (14/194) with IgM-/IgG- had a positive PCR.

CONCLUSION

This study calls for a rapid preparedness and response strategy in higher institutes in the case of any future pathogen with pandemic or epidemic potential. The observed disparity between IgG/IgM and the viral profile supports prioritizing assays targeting the virus (nucleic acid or antigen) for diagnosis and antibody screening for sero-surveys.

Cross-Sectional Study on Lateral Skull Radiographs to Design a New Nasopharyngeal Swab for Simplified COVID-19 and Respiratory Infections Diagnostic Testing in Children

Nasopharyngeal swab sample collection is the first-line testing method for diagnosing COVID-19 infection and other respiratory infections. Current information on how to properly perform nasopharyngeal swabbing in children is largely defective. This study aimed at collecting nostril to nasopharynx distance measurements on lateral skull radiographs of children and adolescents to design a nasopharyngeal swab meant to standardize and facilitate the sample collection procedure. A total of 323 cephalograms of 152 male and 171 female children aged 4-14 years taken for orthodontic reasons were selected. On each cephalogram, the shortest distance between the most anterosuperior point of the nostril contour and the nasopharynx outline was measured in mm parallel to the palatal plane. Descriptive statistics of the measurements were calculated for each age group. The lower limit of the 95% confidence intervals of the measurements was taken as a reference to design a swab shaft with marks that, at each age, delimitate a safety boundary for swab progression up to the posterior nasopharyngeal wall. The simplification of the procedure enabled by the newly designed nasopharyngeal swab is valuable to help healthcare providers perform specimen collection on children in a safe and effective way, perhaps under the less-than-ideal conditions possibly occurring in 'point-of-need' contexts.

Urine Metabolites Enable Fast Detection of COVID-19 Using Mass Spectrometry

The COVID-19 pandemic boosted the development of diagnostic tests to meet patient needs and provide accurate, sensitive, and fast disease detection. Despite rapid advancements, limitations related to turnaround time, varying performance metrics due to different sampling sites, illness duration, co-infections, and the need for particular reagents still exist. As an alternative diagnostic test, we present urine analysis through flow-injection-tandem mass spectrometry (FIA-MS/MS) as a powerful approach for COVID-19 diagnosis, targeting the detection of amino acids and acylcarnitines. We adapted a method that is widely used for newborn screening tests on dried blood for urine samples in order to detect metabolites related to COVID-19 infection. We analyzed samples from 246 volunteers with diagnostic confirmation via PCR. Urine samples were self-collected, diluted, and analyzed with a run time of 4 min. A Lasso statistical classifier was built using 75/25% data for training/validation sets and achieved high diagnostic performances: 97/90% sensitivity, 95/100% specificity, and 95/97.2% accuracy. Additionally, we predicted on two withheld sets composed of suspected hospitalized/symptomatic COVID-19-PCR negative patients and patients out of the optimal time-frame collection for PCR diagnosis, with promising results. Altogether, we show that the benchmarked FIA-MS/MS method is promising for COVID-19 screening and diagnosis, and is also potentially useful after the peak viral load has passed.

Nasopharyngeal swabs vs. saliva sampling for SARS-CoV-2 detection: A cross-sectional survey of acceptability for caregivers and children after experiencing both methods

Background

Saliva sampling is a promising alternative to nasopharyngeal swabs for SARS-CoV-2 testing, but acceptability data is lacking. We characterize the acceptability of saliva sampling and nasopharyngeal swabs for primary decision makers and their children after experiencing both testing modalities.

Methods

We administered a cross-sectional survey to participants aged 6-to-17 years and their primary decision makers at an Ottawa community COVID-19 testing centre in March 2021. Included were participants meeting local guidelines for testing. Excluded were those identified prior to participation as having inability to complete the consent, sampling, or survey process. Acceptability in multiple hypothetical scenarios was rated using a 5-point Likert scale. Pain was measured using the Faces Pain Scale—Revised (FPS-R). Preference for testing was assessed with direct binary questions.

Results

48 participants and 48 primary decision makers completed the survey. Nasopharyngeal swab acceptability differed between scenarios, ranging 79% [95%CI: 66, 88] to 100% [95%CI: 95, 100]; saliva sampling acceptability was similar across scenarios, ranging 92% [95%CI: 82, 97] to 98% [95%CI: 89, 99]. 58% of youth described significant pain with nasopharyngeal swabbing, versus none with saliva sampling. 90% of children prefer saliva sampling. 66% of primary decision makers would prefer nasopharyngeal swabbing if it were 10% more sensitive.

Conclusion

Though youth prefer saliva sampling over nasopharyngeal swabs, primary decision makers present for testing remain highly accepting of both. Acceptance of nasopharyngeal swabs, however, varies with the testing indication and is influenced by perceived test accuracy. Understanding factors that influence sampling acceptance will inform more successful testing strategies.