Assessment of Sensitivity and Specificity of Patient-Collected Lower Nasal Specimens for Severe Acute Respiratory Syndrome Coronavirus 2Testing

A COVID-19 Testing Preference Study in Schools

OBJECTIVES

The Centers for Disease Control and Prevention identifies in-school COVID-19 testing as a key mitigation strategy to protect students and staff during the COVID-19 pandemic. Both nasal and saliva samples are acceptable, but existing school guidance does not state a preferred test method.

METHODS

From May 2021 through July 2021, we performed a randomized, crossover study in kindergarten through 12th grade (K-12) schools to evaluate student and staff preference for self-collected nasal or saliva testing. Participants performed both collection types and participated in a standardized questionnaire assessing the preferred method.

RESULTS

A total of 135 students and staff participated. Staff, middle school, and high school students preferred the nasal swab (80/96, 83%), whereas elementary students were mixed (20/39, 51% preferred saliva). Reasons reported for preferring the nasal swab included being faster and easier. Reasons reported for preferring saliva included being easier and more fun. Despite their preference, 126 (93%) and 109 (81%) participants would take the nasal swab or saliva test again, respectively.

CONCLUSIONS

The anterior nasal test was the preferred testing method by students and staff, although preference varied by age group. Willingness to perform both tests again in the future was high. Identifying the preferred testing modality is important to increase acceptance and participation in COVID-19 in-school testing programs.

Concordance of SARS-CoV-2 Results in Self-collected Nasal Swabs vs Swabs Collected by Health Care Workers in Children and Adolescents

IMPORTANCE

Despite the expansion of SARS-CoV-2 testing, available tests have not received Emergency Use Authorization for performance with self-collected anterior nares (nasal) swabs from children younger than 14 years because the effect of pediatric self-swabbing on SARS-CoV-2 test sensitivity is unknown.

OBJECTIVE

To characterize the ability of school-aged children to self-collect nasal swabs for SARS-CoV-2 testing compared with collection by health care workers.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study of 197 symptomatic children and adolescents aged 4 to 14 years old. Individuals were recruited based on results of testing in the Children's Healthcare of Atlanta system from July to August 2021.

EXPOSURES

Children and adolescents were given instructional material consisting of a short instructional video and a handout with written and visual steps for self-swab collection. Participants first provided a self-collected nasal swab. Health care workers then collected a second specimen.

MAIN OUTCOMES AND MEASURES

The primary outcome was SARS-CoV-2 detection and relative quantitation by cycle threshold (Ct) in self- vs health care worker-collected nasal swabs when tested with a real-time reverse transcriptase-polymerase chain reaction test with Emergency Use Authorization.

RESULTS

Among the study participants, 108 of 194 (55.7%) were male and the median age was 9 years (IQR, 6-11). Of the 196 participants, 87 (44.4%) tested positive for SARS-CoV-2 and 105 (53.6%) tested negative by both self- and health care worker-collected swabs. Two children tested positive by self- or health care worker-collected swab alone; 1 child had an invalid health care worker swab. Compared with health care worker-collected swabs, self-collected swabs had 97.8% (95% CI, 94.7%-100.0%) and 98.1% (95% CI, 95.6%-100.0%) positive and negative percent agreement, respectively, and SARS-CoV-2 Ct values did not differ significantly between groups (mean [SD] Ct, self-swab: 26.7 [5.4] vs health care worker swab: 26.3 [6.0]; P = .65).

CONCLUSIONS AND RELEVANCE

After hearing and seeing simple instructional materials, children and adolescents aged 4 to 14 years self-collected nasal swabs that closely agreed on SARS-CoV-2 detection with swabs collected by health care workers.

A prospective diagnostic evaluation of accuracy of self-taken and healthcare worker-taken swabs for rapid COVID-19 testing

BACKGROUND

Rapid diagnostic tests (RDTs) developed for point of care detection of SARS-CoV-2 antigen are recommended by WHO to use trained health care workers to collect samples. We hypothesised that self-taken samples are non-inferior for use with RDTs to diagnose COVID-19. We designed a prospective diagnostic evaluation comparing self-taken and healthcare worker (HCW)-taken throat/nasal swabs to perform RDTs for SARS-CoV-2, and how these compare to RT-PCR.

METHODS

Eligible participants 18 years or older with symptoms of COVID-19. 250 participants recruited at the NHS Test and Trace drive-through community PCR testing site (Liverpool, UK); one withdrew before analysis. Self-administered throat/nasal swab for the Covios® RDT, a trained HCW taken throat/nasal sample for PCR and HCW comparison throat/nasal swab for RDT were collected. RDT results were compared to RT-PCR, as the reference standard, to calculate sensitivity and specificity.

FINDINGS

Seventy-five participants (75/249, 30.1%) were positive by RT-PCR. RDTs with self-taken swabs had a sensitivity of 90.5% (67/74, 95% CI: 83.9-97.2), compared to 78.4% (58/74, 95% CI: 69.0-87.8) for HCW-taken swabs (absolute difference 12.2%, 95% CI: 4.7-19.6, p = 0.003). Specificity for self-taken swabs was 99.4% (173/174, 95% CI: 98.3-100.0), versus 98.9% (172/174, 95% CI: 97.3-100.0) for HCW-taken swabs (absolute difference 0.6%, 95% CI: 0.5-1.7, p = 0.317). The PPV of self-taken RDTs (98.5%, 67/68, 95% CI: 95.7-100.0) and HCW-taken RDTs (96.7%, 58/60, 95% CI 92.1-100.0) were not significantly different (p = 0.262). However, the NPV of self-taken swab RDTs was significantly higher (96.1%, 173/180, 95% CI: 93.2-98.9) than HCW-taken RDTs (91.5%, 172/188, 95% CI 87.5-95.5, p = 0.003).

INTERPRETATION

In conclusion, self-taken swabs for COVID-19 testing offer an accurate alternative to healthcare worker taken swabs for use with RDTs. Our results demonstrate that, with no training, self-taken throat/nasal samples can be used by lay individuals as part of rapid testing programmes for symptomatic adults. This is especially important where the lack of trained healthcare workers restricts access to testing.

Perceptions of COVID-19 self-testing and recommendations for implementation and scale-up among Black/African Americans: implications for the COVID-19 STEP project

BACKGROUND

COVID-19 self-testing (ST) is an innovative strategy with the potential to increase the access and uptake of testing and ultimately to limit the spread of the virus. To maximize the uptake and reach of this promising strategy and inform intervention development and scale up, research is needed to understand the acceptability of and willingness to use this tool. This is vital to ensure that Black/African Americans are reached by the Biden-Harris Administration's free national COVID-19 ST program. This study aimed to explore the acceptability and recommendations to promote and scale-up the uptake of COVID-19 ST among Black/African Americans.

METHODS

We conducted a cross-sectional qualitative study using a semi-structured questionnaire to assess barriers and facilitators to the uptake of COVID-19 ST among a convenience sample of 28 self-identified Black/African Americans from schools, community centers, and faith-based institutions in Ohio and Maryland. Inductive content analysis was conducted to identify categories and subcategories related to acceptability and recommendations for implementing and scaling up COVID-19 ST in communities.

RESULTS

Participants perceived COVID-19 self-testing as an acceptable tool that is beneficial to prevent transmission and address some of the barriers associated with health facility testing, such as transportation cost and human contact at the health facility. However, concerns were raised regarding the accurate use of the kits and costs. Recommendations for implementing and scaling up COVID-19 ST included engagement of community stakeholders to disseminate information about COVID-19 self-testing and creating culturally appropriate education tools to promote knowledge of and clear instructions about how to properly use COVID-19 ST kits. Based on these recommendations, the COVID-19 STEP (Self-Testing Education and Promotion) Project is being developed and will involve engaging community partners such as barbers, church leaders, and other community-based organizations to increase the uptake and use of free COVID-19 ST kits among Black/African Americans.

CONCLUSION

Findings showed that most participants considered COVID-19 ST valuable for encouraging COVID-19 testing. However, cost and accuracy concerns may pose barriers. Future work should consider implementing interventions that leverage the benefits of COVID-19 ST and further assess the extent to which these identified facilitators and barriers may influence COVID-19 ST uptake.

Lessons Learned From a COVID-19 Biohazard Spill During Swabbing at a Quarantine Facility

The need for increased testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), has resulted in an increase of testing facilities outside of traditional clinical settings and sample handling by individuals without appropriate biohazard and biocontainment training. During the repatriation and quarantine of passengers from the Grand Princess cruise ship at a US military base, biocontainment of a potentially infectious sample from a passenger was compromised. This study describes the steps taken to contain the spill, decontaminate the area, and discusses the needs for adequate training in a biohazard response.

Sensitivity and Specificity of SARS-CoV-2 Rapid Antigen Detection Tests Using Oral, Anterior Nasal, and Nasopharyngeal Swabs: a Diagnostic Accuracy Study

The objective of our study was to evaluate the sensitivity and specificity of rapid antigen detection tests versus those of reverse transcriptase PCR (RT-PCR) using oral, anterior nasal, and nasopharyngeal swabs. The underlying prospective, diagnostic case-control-type accuracy study included 87 hospitalized and nonhospitalized participants in a positive and a negative sample cohort between 16 March and 14 May 2021 in two hospitals in Vienna. SARS-CoV-2 infection status was confirmed by RT-PCR. Participants self-performed one oral and one anterior nasal swab for the rapid antigen test, immediately followed by two nasopharyngeal swabs for the rapid antigen test and RT-PCR by the investigator. Test results were read after 15 min, and participants completed a questionnaire in the meantime. Test parameters were calculated based on the evaluation of 87 participants. The overall sensitivity of rapid antigen detection tests versus that of RT-PCR with oral, anterior nasal, and nasopharyngeal samples was 18.18% (95% confidence interval [CI] 8.19% to 32.71%), 63.04% (95% CI 47.55% to 76.79%), and 73.33% (95% CI 58.06% to 85.4%), respectively. All sampling methods had a test specificity of 100% regardless of the cycle threshold (CT) value. Rapid antigen detection tests using self-collected anterior nasal swabs proved to be as sensitive as and more tolerable than professionally collected nasopharyngeal swabs for CT values up to 30 determined by RT-PCR. This finding illustrates the reliability of tests obtained by adequate self-collected anterior nasal specimen. Sensitivity was dependent upon the CT value for each sampling method. While the main advantage of rapid antigen detection tests is the immediate availability of results, PCR should be preferred in crucial settings wherever possible. IMPORTANCE Rapid antigen detection devices for SARS-CoV-2 represent a valuable tool for monitoring the spread of infection. However, the reliability of the tests depends largely on the test performance and the respective sampling method. Nasopharyngeal swabs mark the gold standard for sample collection in suspected respiratory tract infections but are unsuitable for widespread application, as they must be performed by medically trained personnel. With the underlying study, the head-to-head test performance and the usability of self-collected samples for SARS-CoV-2 detection using rapid antigen detection devices were evaluated. The results confirm similar sensitivity of self-collected anterior nasal swabs to that of professionally collected nasopharyngeal swabs for patients with a CT of < 30 determined by RT-PCR.

Perceptions of COVID-19 Self-Testing and Recommendations for Implementation and Scale up Among Black/African Americans: Implications for the COVID-19 STEP Project

Background COVID-19 self-testing (ST) is an innovative strategy with the potential to increase the access and uptake of testing and ultimately to limit the spread of the virus. To maximize the uptake and reach of this promising strategy and inform intervention development and scale up, research is needed to understand the acceptability of and willingness to use this tool. This is vital to ensure that Black/African Americans are reached by the Biden-Harris Administration’s free national COVID-19 ST program. This study aimed to explore the acceptability and recommendations to promote and scale up the uptake of COVID-19 ST among Black/African Americans. Methods We conducted a cross-sectional qualitative study using a semi-structured survey to assess barriers and facilitators to the uptake of COVID-19 ST among a convenience sample of 28 self-identified Black/African Americans from schools, community centers, and faith-based institutions in Ohio and Maryland. Inductive content analysis was conducted to identify categories and subcategories related to acceptability and recommendations for implementing and scaling up COVID-19 ST in communities. Results Participants perceived COVID-19 self-testing as an acceptable tool that is beneficial to prevent transmission and address some of the barriers associated with health facility testing, such as transportation cost and human contact at the health facility. However, concerns were raised regarding the accurate use of the kits and costs. Recommendations for implementing and scaling up COVID-19 ST included engagement of community stakeholders to disseminate information about COVID-19 self-testing and creating culturally appropriate education tools to promote knowledge of and clear instructions about how to properly use COVID-19 ST kits. Based on these recommendations, the COVID-19 STEP (Self-Testing Education and Promotion) Project is being developed and will involve engaging community partners such as barbers, church leaders, and other community-based organizations to increase the uptake and use of free COVID-19 ST kits among Black/African Americans. Conclusion Findings showed that most participants considered COVID-19 ST valuable for encouraging COVID-19 testing. However, cost and accuracy concerns may pose barriers. Future work should consider implementing interventions that leverage the benefits of COVID-19 ST and further assess the extent to which these identified facilitators and barriers may influence COVID-19 ST uptake.

Diagnostic Performance, Stability, and Usability of Self-Collected Combo Swabs and Saliva for Coronavirus Disease 2019 Diagnosis: A Case-Control Study

Background

Self-sampling procedures to detect severe acute respiratory syndrome coronavirus 2 is important for patients who have difficulty visiting the hospital and may decrease the burden for health care workers (HCWs). The objective of this study was to evaluate the diagnostic performance, stability and usability of self-collected nasal and oral combo swabs and saliva specimens.

Materials and Methods

We conducted a case-control study with 50 patients with coronavirus disease 2019 (COVID-19) and 50 healthy volunteers from March, 2021 to June, 2021. We performed real-time reverse-transcription polymerase chain reaction to compare the diagnostic performance of self-collected specimens using positive percent agreements (PPAs).

Results

The PPAs between self-collected and HCW-collected specimens were 77.3 - 81.0% and 80.5 -86.7% for the combo swabs and saliva specimens, respectively. The PPAs increased to 88.9 - 89.2% and 81.2 - 82.1% with a cycle threshold value ≤30.

Conclusion

The diagnostic performance of self sampling was comparable to that of HCW sampling in patients with high viral loads and may thus assist in the early diagnosis of COVID-19.

Rapid and sensitive detection of SARS-CoV-2 infection using quantitative peptide enrichment LC-MS analysis

Reliable, robust, large-scale molecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for monitoring the ongoing coronavirus disease 2019 (COVID-19) pandemic. We have developed a scalable analytical approach to detect viral proteins based on peptide immuno-affinity enrichment combined with liquid chromatography-mass spectrometry (LC-MS). This is a multiplexed strategy, based on targeted proteomics analysis and read-out by LC-MS, capable of precisely quantifying and confirming the presence of SARS-CoV-2 in phosphate-buffered saline (PBS) swab media from combined throat/nasopharynx/saliva samples. The results reveal that the levels of SARS-CoV-2 measured by LC-MS correlate well with their correspondingreal-time polymerase chain reaction (RT-PCR) read-out (r = 0.79). The analytical workflow shows similar turnaround times as regular RT-PCR instrumentation with a quantitative read-out of viral proteins corresponding to cycle thresholds (Ct) equivalents ranging from 21 to 34. Using RT-PCR as a reference, we demonstrate that the LC-MS-based method has 100% negative percent agreement (estimated specificity) and 95% positive percent agreement (estimated sensitivity) when analyzing clinical samples collected from asymptomatic individuals with a Ct within the limit of detection of the mass spectrometer (Ct ≤ 30). These results suggest that a scalable analytical method based on LC-MS has a place in future pandemic preparedness centers to complement current virus detection technologies.

The COVID-19 Self-Testing through Rapid Network Distribution (C-STRAND) trial: A randomized controlled trial to increase COVID-19 testing in underserved populations

Background Widely available population testing is critical to public health efforts to control the ongoing COVID-19 pandemic. However, COVID-19 testing has been low in underserved communities disproportionately affected by COVID-19. One approach to increase testing rates is through the secondary distribution of self-collection kits, where an individual distributes test kits to contacts in their social network and encourages them to self-collect test specimens. We outline a randomized clinical trial, COVID-19 Self-testing Through Rapid Network Distribution (C-STRAND), and a cohort study of individuals with COVID-19, to determine the impact of a secondary distribution strategy on COVID-19 testing among medically underserved populations. Methods The clinical trial will seek to enroll 1048 adult index participants from federally health qualified centers in Philadelphia, PA seeking COVID-19 testing. Eligible participants will be randomized 1:1 to receive multiple self-collection test kits or multiple referrals for standard clinic-based tests to distribute to contacts within their social network. The primary outcome will be testing among at least two network contacts at 8 weeks. Index participants and network contacts who test positive for COVID-19 from C-STRAND will be eligible to join the COVID-19 Close Contact Self-testing Study (CloseST), assessing the secondary distribution of self-collection test kits among individuals with COVID-19. The primary outcome of this cohort will be the number of close contacts who test positive at 8 weeks. Conclusion Novel strategies to promote COVID-19 testing are necessary, particularly among underserved populations most affected by COVID-19. We will determine the efficacy of a self-testing secondary distribution strategy. The results may inform efforts to increase testing rates during the current pandemic.

Usability of an At-Home Anterior Nares SARS-CoV-2 RT-PCR Sample Collection Kit: Human Factors Feasibility Study

Background

Readily available testing for SARS-CoV-2 is necessary to mitigate COVID-19 disease outbreaks. At-home collection kits, in which samples are self-collected without requiring a laboratory or clinic visit and sent to an external laboratory for testing, can provide convenient testing to those with barriers to access. They can prevent unnecessary exposure between patient and clinical staff, increase access for patients with disabilities or remote workers, and decrease burdens on health care resources, such as provider time and personal protective equipment. Exact Sciences developed an at-home collection kit for samples to be tested to detect SARS-CoV-2 that includes an Instructions for Use (IFU) document, which guides people without prior experience on collecting a nasal swab sample. Demonstrating successful sample collection and usability is critical to ensure that these samples meet the same high-quality sample collection standards as samples collected in clinics.

Objective

The aim of this study was to determine the usability of a SARS-CoV-2 at-home nasal swab sample collection kit.

Methods

A human factors usability study was conducted with 30 subjects without prior medical, laboratory, or health care training and without COVID-19 sample self-collection experience. Subjects were observed while they followed the IFU for the at-home sample collection portion of the SARS-CoV-2 test in a setting that simulated a home environment. IFU usability was further evaluated by requiring the subjects to complete a survey, answer comprehension questions, provide written feedback, and respond to questions from the observer about problems during use.

Results

All 30 subjects successfully completed the sample collection process, and all 30 samples were determined by reverse transcription–polymerase chain reaction (RT-PCR) testing to meet quality standards for SARS-CoV-2 testing. The subjects’ written feedback and comments revealed several recommendations to improve the IFU.

Conclusions

The study demonstrated the overall usability of an at-home SARS-CoV-2 collection kit. Various feedback mechanisms provided opportunities to improve the wording and graphics for some critical tasks, including placing the label correctly on the tube. A modified IFU was prepared based on study outcomes.

Accuracy and Acceptance of a Self-Collection Model for Respiratory Tract Infection Diagnostics: A Concise Clinical Literature Review

Background

Nurses are the primary clinicians who collect specimens for respiratory tract infection testing. The specimen collection procedure is time and resource-consuming, but more importantly, it places nurses at risk for potential infection. The practice of allowing patients to self-collect their diagnostic specimens may provide an alternative testing model for the current COVID-19 outbreaks. The objective of this paper was to evaluate the accuracy and patient perception of self-collected specimens for respiratory tract infection diagnostics.

Methods

A concise clinical review of the recently published literature was conducted.

Results

A total of 11 articles were included the review synthesis. The concept of self-collected specimens has a high patient acceptance rate of 83-99%. Self-collected nasal-swab specimens demonstrated strong diagnostic fidelity for respiratory tract infections with a sensitivity between 80-100%, this is higher than the 76% sensitivity observed with self-collected throat specimens. In a comparative study evaluating a professionally collected to a self-collected specimen for COVID-19 testing, a high degree of agreement (k = 0.89) was observed between the two methods.

Conclusion

As we continue to explore for testing models to combat the COVID-19 pandemic, self-collected specimens is a practical alternative to nurse specimen collection.

Variation in SARS-CoV-2 molecular test sensitivity by specimen types in a large sample of emergency department patients

BACKGROUND

Provider-collected nasopharyngeal specimens for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) molecular testing are the standard of care in many clinical settings, but patient-collected saliva and anterior nares specimens are less invasive and more flexible alternatives. Prior studies comparing specimen types for SARS-CoV-2 molecular testing have been limited by small sample sizes and low pretest probability. We conducted a large observational study among symptomatic adults at 7 emergency departments of Kaiser Permanente Southern California to examine sensitivity of SARS-CoV-2 molecular tests by specimen type and patient characteristics.

METHODS

Provider-collected nasopharyngeal/oropharyngeal (NP/OP) specimens and patient-collected saliva and anterior nares specimens were collected at the same visit and analyzed with the Roche cobas® SARS-CoV-2 assay. Patients were considered truly positive for SARS-CoV-2 if any of the three specimens was positive and negative if all three specimens were negative. Factors associated with discordant and missed positive results were examined with multivariable logistic regression.

RESULTS

Of 2112 patients, 350 (16.6%) were positive for SARS-CoV-2. Sensitivity of NP/OP was 93.7% (95% confidence interval [CI] 90.6%-96.0%), sensitivity of saliva was 87.7% (83.8%-91.0%), and sensitivity of anterior nares was 85.4% (81.3%-89.0%). Patients ages 18-39 years versus ≥40 years were more likely to have discordant results [adjusted odds ratio (aOR) 1.97 (1.12-3.45)], as were patients with <4 symptoms versus ≥4 [aOR 2.43 (1.39-4.25)]. Cycle threshold values were higher for saliva and anterior nares than NP/OP specimens, as well as for specimens in discordant versus concordant sets and patients with fewer symptoms.

CONCLUSION

This study provides robust evidence that patient-collected saliva and anterior nares are sensitive for SARS-CoV-2 molecular testing in emergency department settings, particularly among adults ages ≥40 years and those with multiple symptoms. Higher sensitivity of provider-collected NP/OP specimens must be weighed against the benefits of patient-collected specimens in tailored strategies for SARS-CoV-2 testing.

Standardized reporting systems of chest computed tomography in a population with low coronavirus disease 2019 prevalence: A retrospective comparative study

Purpose

To compare the diagnostic performance and interobserver agreement of three reporting systems for computed tomography findings in coronavirus disease 2019 (COVID-19), namely the COVID-19 Reporting and Data System (CO-RADS), COVID-19 Imaging Reporting and Data System (COVID-RADS), and Radiological Society of North America (RSNA) expert consensus statement, in a low COVID-19 prevalence area.

Method

This institutional review board approval single-institutional retrospective study included 154 hospitalized patients between April 1 and May 21, 2020; 26 (16.9 %; 63.2 ± 14.1 years, 21 men) and 128 (65.7 ± 16.4 years, 87 men) patients were diagnosed with and without COVID-19 according to reverse transcription-polymerase chain reaction results, respectively. Written informed consent was waived due to the retrospective nature of the study. Six radiologists independently classified chest computed tomography images according to each reporting system. The area under receiver operating characteristic curves, sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and interobserver agreements were calculated and compared across the systems using paired t-test and kappa analysis.

Results

Mean area under receiver operating characteristic curves were as follows: CO-RADS, 0.89 (95 % confidence interval [CI], 0.87–0.90); COVID-RADS, 0.78 (0.75–0.80); and RSNA expert consensus statement, 0.88 (0.86–0.90). Average kappa values across observers were 0.52 (95 % CI: 0.45–0.60), 0.51 (0.41–0.61), and 0.57 (0.49–0.64) for CO-RADS, COVID-RADS, and RSNA expert consensus statement, respectively. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were the highest at 0.71, 0.53, 0.72, 0.96, and 0.56 in the CO-RADS; 0.56, 0.31, 0.54, 0.95, and 0.35 in the COVID-RADS; 0.83, 0.49, 0.61, 0.96, and 0.55 in the RSNA expert consensus statement, respectively.

Conclusions

The CO-RADS exhibited the highest specificity, positive predictive value, which are especially important in a low-prevalence population, while maintaining high accuracy and negative predictive value, demonstrating the best performance in a low-prevalence population.

Effects of Patient Characteristics on Diagnostic Performance of Self-Collected Samples for SARS-CoV-2 Testing

We evaluated the performance of self-collected anterior nasal swab (ANS) and saliva samples compared with healthcare worker–collected nasopharyngeal swab specimens used to test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We used the same PCR diagnostic panel to test all self-collected and healthcare worker–collected samples from participants at a public hospital in Atlanta, Georgia, USA. Among 1,076 participants, 51.9% were men, 57.1% were >50 years of age, 81.2% were Black (non-Hispanic), and 74.9% reported >1 chronic medical condition. In total, 8.0% tested positive for SARS-CoV-2. Compared with nasopharyngeal swab samples, ANS samples had a sensitivity of 59% and saliva samples a sensitivity of 68%. Among participants tested 3–7 days after symptom onset, ANS samples had a sensitivity of 80% and saliva samples a sensitivity of 85%. Sensitivity varied by specimen type and patient characteristics. These findings can help physicians interpret PCR results for SARS-CoV-2.

A Practical Approach to Hospital Visitation During a Pandemic: Responding With Compassion to Unjustified Restrictions

During the COVID-19 pandemic, evidence-based resources have been sought to support decision-making and strategically inform hospitals' policies, procedures, and practices. While greatly emphasizing protection, most guiding documents have neglected to support and protect the psychosocial needs of frontline health care workers and patients and their families during provision of palliative and end-of-life care. Consequently, the stage has been set for increased anxiety, moral distress, and moral injury and extreme moral hazard. A family-centered approach to care has been unilaterally relinquished to a secondary and nonessential role during the current crisis. This phenomenon violates a foundational public health principle, namely, to apply the least restrictive means to achieve good for the many. Instead, there has been widespread adoption of utilitarian and paternalistic approaches. In many cases the foundational principles of palliative care have also been neglected. No circumstance, even a global public health emergency, should ever cause health care providers to deny their ethical obligations and human commitment to compassion. The lack of responsive protocols for family visitation, particularly at the end of life, is an important gap in the current recommendations for pandemic triage and contingency planning. A stepwise approach to hospital visitation using a tiered, standardized process for responding to emerging clinical circumstances and individual patients' needs should be considered, following the principle of proportionality. A contingency plan, based on epidemiological data, is the best strategy to refocus health care ethics in practice now and for the future.

Evaluating an app-guided self-test for influenza: lessons learned for improving the feasibility of study designs to evaluate self-tests for respiratory viruses

Background

Seasonal influenza leads to significant morbidity and mortality. Rapid self-tests could improve access to influenza testing in community settings. We aimed to evaluate the diagnostic accuracy of a mobile app-guided influenza rapid self-test for adults with influenza like illness (ILI), and identify optimal methods for conducting accuracy studies for home-based assays for influenza and other respiratory viruses.

Methods

This cross-sectional study recruited adults who self-reported ILI online. Participants downloaded a mobile app, which guided them through two low nasal swab self-samples. Participants tested the index swab using a lateral flow assay. Test accuracy results were compared to the reference swab tested in a research laboratory for influenza A/B using a molecular assay.

Results

Analysis included 739 participants, 80% were 25–64 years of age, 79% female, and 73% white. Influenza positivity was 5.9% based on the laboratory reference test. Of those who started their test, 92% reported a self-test result. The sensitivity and specificity of participants’ interpretation of the test result compared to the laboratory reference standard were 14% (95%CI 5–28%) and 90% (95%CI 87–92%), respectively.

Conclusions

A mobile app facilitated study procedures to determine the accuracy of a home based test for influenza, however, test sensitivity was low. Recruiting individuals outside clinical settings who self-report ILI symptoms may lead to lower rates of influenza and/or less severe disease. Earlier identification of study subjects within 48 h of symptom onset through inclusion criteria and rapid shipping of tests or pre-positioning tests is needed to allow self-testing earlier in the course of illness, when viral load is higher.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06314-1.

A Systematic Review and Meta-analysis of Upper Airway Swab Collection for Detection of Viral and Bacterial Pathogens by Individuals or Caregivers Compared to Health Care Workers

Self- or caregiver collection of upper airway swabs reduces infectious exposures of health care workers (HCWs) and the need to redeploy clinical staff to testing roles. We aimed to determine whether self- or caregiver collection has adequate diagnostic performance for detection of viral and bacterial upper airway pathogens. We did a systematic review and meta-analysis of studies comparing diagnostic accuracy of self- or caregiver-collected upper airway swabs collected by patients or caregivers compared to HCWs. All study types except case reports and series were included if sufficient data were presented to calculate sensitivity, specificity, and Cohen's kappa. Studies published from 1946 to 17 August 2020 were included in the search. We did a meta-analysis to assess pooled sensitivity and specificity. Twenty studies were included in the systematic review and 15 in the meta-analysis. The overall sensitivity of swabs collected by patients or caregivers compared to HCWs was 91% (95% confidence interval [CI], 87 to 94), and specificity was 98% (95% CI, 96 to 99). Sensitivity ranged from 65% to 100% and specificity from 73% to 100% across the studies. All but one study concluded that self- or caregiver-collected swabs were acceptable for detection of upper airway pathogens. Self- and caregiver collection of upper airway swabs had reassuring diagnostic performance for multiple pathogens. There are numerous potential benefits of self- and caregiver-collected swabs for patients, families, researchers, and health systems. Further research to optimize implementation of sample collection by patients and caregivers is warranted.

Delayed Rise of Oral Fluid Antibodies, Elevated BMI, and Absence of Early Fever Correlate With Longer Time to SARS-CoV-2 RNA Clearance in a Longitudinally Sampled Cohort of COVID-19 Outpatients

BACKGROUND

Sustained molecular detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in the upper respiratory tract (URT) in mild to moderate coronavirus disease 2019 (COVID-19) is common. We sought to identify host and immune determinants of prolonged SARS-CoV-2 RNA detection.

METHODS

Ninety-five symptomatic outpatients self-collected midturbinate nasal, oropharyngeal (OP), and gingival crevicular fluid (oral fluid) samples at home and in a research clinic a median of 6 times over 1-3 months. Samples were tested for viral RNA, virus culture, and SARS-CoV-2 and other human coronavirus antibodies, and associations were estimated using Cox proportional hazards models.

RESULTS

Viral RNA clearance, as measured by SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR), in 507 URT samples occurred a median (interquartile range) 33.5 (17-63.5) days post-symptom onset. Sixteen nasal-OP samples collected 2-11 days post-symptom onset were virus culture positive out of 183 RT-PCR-positive samples tested. All participants but 1 with positive virus culture were negative for concomitant oral fluid anti-SARS-CoV-2 antibodies. The mean time to first antibody detection in oral fluid was 8-13 days post-symptom onset. A longer time to first detection of oral fluid anti-SARS-CoV-2 S antibodies (adjusted hazard ratio [aHR], 0.96; 95% CI, 0.92-0.99; P = .020) and body mass index (BMI) ≥25 kg/m2 (aHR, 0.37; 95% CI, 0.18-0.78; P = .009) were independently associated with a longer time to SARS-CoV-2 viral RNA clearance. Fever as 1 of first 3 COVID-19 symptoms correlated with shorter time to viral RNA clearance (aHR, 2.06; 95% CI, 1.02-4.18; P = .044).

CONCLUSIONS

We demonstrate that delayed rise of oral fluid SARS-CoV-2-specific antibodies, elevated BMI, and absence of early fever are independently associated with delayed URT viral RNA clearance.

Polyester nasal swabs collected in a dry tube are a robust and inexpensive, minimal self-collection kit for SARS-CoV-2 testing

BACKGROUND

In order to identify an inexpensive yet highly stable SARS-CoV-2 collection device as an alternative to foam swabs stored in transport media, both contrived ("surrogate") CoV-positive and patient-collected spun polyester swabs stored in dry tubes were evaluated for time- and temperature-stability using qPCR.

METHODS

Surrogate specimens were prepared by combining multiple, residual SARS-CoV-2-positive clinical specimens and diluting to near-LOD levels in either porcine or human mucus ("matrix"), inoculating foam or polyester nasal swabs, and sealing in dry tubes. Swabs were then subjected to one of three temperature excursions: (1) 4°C for up to 72 hours; (2) 40°C for 12 hours, followed by 32°C for up to 60 hours; or (3) multiple freeze-thaw cycles (-20°C). The stability of extracted SARS-CoV-2 RNA for each condition was evaluated by qPCR. Separate usability studies for the dry polyester swab-based HealthPulse@home COVID-19 Specimen Collection Kit were later conducted in both adult and pediatric populations.

RESULTS

Polyester swabs stored dry demonstrated equivalent performance to foam swabs for detection of low and moderate SARS-CoV-2 viral loads. Mimicking warm- and cold- climate shipment, surrogate specimens were stable following either 72 hours of a high-temperature excursion or two freeze-thaw cycles. In addition, usability studies comprised of self-collected patient specimens yielded sufficient material for molecular testing, as demonstrated by RNase P detection.

CONCLUSIONS

Polyester nasal swabs stored in dry collection tubes offer a robust and inexpensive self-collection method for SARS-CoV-2 viral load testing, as viral RNA remains stable under conditions required for home collection and shipment to the laboratory.

Adherence to Public Health Measures Mitigates the Risk of COVID-19 Infection in Older Adults: A Community-Based Study

OBJECTIVE

To assess the prevalence and characteristics of coronavirus disease 2019 (COVID-19) cases during the reopening period in older adults, given that little is known about the prevalence of COVID-19 after the stay-at-home order was lifted in the United States, nor the actual effects of adherence to recommended public health measures (RPHM) on the risk of COVID-19.

PATIENTS AND METHODS

This was a cross-sectional study nested in a parent prospective cohort study, which followed a population-based sample of 2325 adults 50 years and older residing in southeast Minnesota to assess the incidence of viral infections. Participants were instructed to self-collect both nasal and oropharyngeal swabs, which were tested by reverse transcription polymerase chain reaction-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assay between May 8, 2020, and June, 30, 2020. We assessed the prevalence of COVID-19 cases and characteristics of study subjects.

RESULTS

A total of 1505 eligible subjects participated in the study whose mean age was 68 years, with 885 (59%) women, 32 (2%) racial/ethnic minorities, and 906 (60%) with high-risk conditions for influenza. The prevalence of other Coronaviridae (human coronavirus [HCoV]-229E, HCoV-NL63, and HCoV-OC43) during the 2019 to 2020 flu season was 109 (7%), and none tested positive for SARS-CoV-2. Almost all participants reported adhering to the RPHM (1,488 [99%] for social distancing, 1,438 [96%] for wearing mask in a public space, 1,476 [98%] for hand hygiene, and 1,441 (96%) for staying home mostly). Eighty-six percent of participants resided in a single-family home.

CONCLUSION

We did not identify SARS-COV-2 infection in our study cohort. The combination of participants' behavior in following the RPHM and their living environment may considerably mitigate the risk of COVID-19.

Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) screening among symptom-free healthcare workers

Transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is possible among symptom-free individuals. Patients are avoiding medically necessary healthcare visits for fear of becoming infected in the healthcare setting. We screened 489 symptom-free healthcare workers for SARS-CoV-2 and found no positive results, strongly suggesting that the prevalence of SARS-CoV-2 was <1%.

Delayed rise of oral fluid antibodies, elevated BMI, and absence of early fever correlate with longer time to SARS-CoV-2 RNA clearance in an longitudinally sampled cohort of COVID-19 outpatients

Background

Sustained molecular detection of SARS-CoV-2 RNA in the upper respiratory tract (URT) in mild to moderate COVID-19 is common. We sought to identify host and immune determinants of prolonged SARS-CoV-2 RNA detection.

Methods

Ninety-five outpatients self-collected mid-turbinate nasal, oropharyngeal (OP), and gingival crevicular fluid (oral fluid) samples at home and in a research clinic a median of 6 times over 1-3 months. Samples were tested for viral RNA, virus culture, and SARS-CoV-2 and other human coronavirus antibodies, and associations were estimated using Cox proportional hazards models.

Results

Viral RNA clearance, as measured by SARS-CoV-2 RT-PCR, in 507 URT samples occurred a median (IQR) 33.5 (17-63.5) days post-symptom onset. Sixteen nasal-OP samples collected 2-11 days post-symptom onset were virus culture positive out of 183 RT-PCR positive samples tested. All participants but one with positive virus culture were negative for concomitant oral fluid anti-SARS-CoV-2 antibodies. The mean time to first antibody detection in oral fluid was 8-13 days post-symptom onset. A longer time to first detection of oral fluid anti-SARS-CoV-2 S antibodies (aHR 0.96, 95% CI 0.92-0.99, p=0.020) and BMI ≥ 25kg/m ² (aHR 0.37, 95% CI 0.18-0.78, p=0.009) were independently associated with a longer time to SARS-CoV-2 viral RNA clearance. Fever as one of first three COVID-19 symptoms correlated with shorter time to viral RNA clearance (aHR 2.06, 95% CI 1.02-4.18, p=0.044).

Conclusions

We demonstrate that delayed rise of oral fluid SARS-CoV-2-specific antibodies, elevated BMI, and absence of early fever are independently associated with delayed URT viral RNA clearance.

Influenza and Respiratory Virus Surveillance, Vaccine Uptake, and Effectiveness at a Time of Cocirculating COVID-19: Protocol for the English Primary Care Sentinel System for 2020-2021

Background

The Oxford–Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) and Public Health England (PHE) are commencing their 54th season of collaboration at a time when SARS-CoV-2 infections are likely to be cocirculating with the usual winter infections.

Objective

The aim of this study is to conduct surveillance of influenza and other monitored respiratory conditions and to report on vaccine uptake and effectiveness using nationally representative surveillance data extracted from primary care computerized medical records systems. We also aim to have general practices collect virology and serology specimens and to participate in trials and other interventional research.

Methods

The RCGP RSC network comprises over 1700 general practices in England and Wales. We will extract pseudonymized data twice weekly and are migrating to a system of daily extracts. First, we will collect pseudonymized, routine, coded clinical data for the surveillance of monitored and unexpected conditions; data on vaccine exposure and adverse events of interest; and data on approved research study outcomes. Second, we will provide dashboards to give general practices feedback about levels of care and data quality, as compared to other network practices. We will focus on collecting data on influenza-like illness, upper and lower respiratory tract infections, and suspected COVID-19. Third, approximately 300 practices will participate in the 2020-2021 virology and serology surveillance; this will include responsive surveillance and long-term follow-up of previous SARS-CoV-2 infections. Fourth, member practices will be able to recruit volunteer patients to trials, including early interventions to improve COVID-19 outcomes and point-of-care testing. Lastly, the legal basis for our surveillance with PHE is Regulation 3 of the Health Service (Control of Patient Information) Regulations 2002; other studies require appropriate ethical approval.

Results

The RCGP RSC network has tripled in size; there were previously 100 virology practices and 500 practices overall in the network and we now have 322 and 1724, respectively. The Oxford–RCGP Clinical Informatics Digital Hub (ORCHID) secure networks enable the daily analysis of the extended network; currently, 1076 practices are uploaded. We are implementing a central swab distribution system for patients self-swabbing at home in addition to in-practice sampling. We have converted all our primary care coding to Systematized Nomenclature of Medicine Clinical Terms (SNOMED CT) coding. Throughout spring and summer 2020, the network has continued to collect specimens in preparation for the winter or for any second wave of COVID-19 cases. We have collected 5404 swabs and detected 623 cases of COVID-19 through extended virological sampling, and 19,341 samples have been collected for serology. This shows our preparedness for the winter season.

Conclusions

The COVID-19 pandemic has been associated with a groundswell of general practices joining our network. It has also created a permissive environment in which we have developed the capacity and capability of the national primary care surveillance systems and our unique public health institute, the RCGP and University of Oxford collaboration.

Analytical Sensitivity of the Abbott BinaxNOW COVID-19 Ag Card

Multiple rapid antigen (Ag) tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have recently received emergency-use authorization (EUA) from the U.S. Food and Drug Administration (FDA).

Multiple rapid antigen (Ag) tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have recently received emergency-use authorization (EUA) from the U.S. Food and Drug Administration (FDA). Although less sensitive than molecular detection methods, rapid antigen testing offers the potential for inexpensive, quick, decentralized testing. Robust analytical sensitivity data in comparison to reverse transcription-quantitative PCR (qRT-PCR) are currently lacking for many rapid antigen tests. Here, we evaluated the analytical sensitivity of the Abbott BinaxNOW COVID-19 Ag card using SARS-CoV-2-positive clinical specimens quantified by reverse transcription-droplet digital PCR (RT-ddPCR) and multiple FDA EUA qRT-PCR platforms using RNA standards. Initial and confirmatory limits of detection for the BinaxNOW COVID-19 Ag card were determined to be equivalent to 4.04 × 10⁴ to 8.06 × 10⁴ copies/swab. We further confirmed this limit of detection with 72 additional clinical samples positive for SARS-CoV-2 in either phosphate-buffered saline or viral transport medium. One hundred percent of samples with viral loads of >40,000 copies/swab were detected by rapid antigen testing. These data indicate that the BinaxNOW COVID-19 Ag card has an analytical sensitivity approximately equivalent to a generic qRT-PCR cycle threshold (C_T) value of 29 to 30.

Shifting Coronavirus Disease 2019 Testing Policy and Research to Include the Full Translation Pipeline

The current severe acute respiratory syndrome coronavirus 2 testing policy and practice limits testing as a prevention tool. Radical shifts are required to increase the scale of rapid testing strategies and improve dissemination and implementation of venue-based and self-testing approaches. Attention to the full translation pipeline is required to reach high-risk segments of the population.

Self-Collected Oral Fluid Saliva Is Insensitive Compared With Nasal-Oropharyngeal Swabs in the Detection of Severe Acute Respiratory Syndrome Coronavirus 2 in Outpatients

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic control will require widespread access to accurate diagnostics. Salivary sampling circumvents swab supply chain bottlenecks, is amenable to self-collection, and is less likely to create an aerosol during collection compared with the nasopharyngeal swab.

METHODS

We compared real-time reverse-transcription polymerase chain reaction Abbott m2000 results from matched salivary oral fluid (gingival crevicular fluid collected in an Oracol device) and nasal-oropharyngeal (OP) self-collected specimens in viral transport media from a nonhospitalized, ambulatory cohort of coronavirus disease 2019 (COVID-19) patients at multiple time points. These 2 sentences should be at the beginning of the results.

RESULTS

There were 171 matched specimen pairs. Compared with nasal-OP swabs, 41.6% of the oral fluid samples were positive. Adding spit to the oral fluid percent collection device increased the percent positive agreement from 37.2% (16 of 43) to 44.6% (29 of 65). The positive percent agreement was highest in the first 5 days after symptoms and decreased thereafter. All of the infectious nasal-OP samples (culture positive on VeroE6 TMPRSS2 cells) had a matched SARS-CoV-2 positive oral fluid sample.

CONCLUSIONS

In this study of nonhospitalized SARS-CoV-2-infected persons, we demonstrate lower diagnostic sensitivity of self-collected oral fluid compared with nasal-OP specimens, a difference that was especially prominent more than 5 days from symptom onset. These data do not justify the routine use of oral fluid collection for diagnosis of SARS-CoV-2 despite the greater ease of collection. It also underscores the importance of considering the method of saliva specimen collection and the time from symptom onset especially in outpatient populations.

Factors Associated With US Public Motivation to Use and Distribute COVID-19 Self-tests

This survey study examines factors associated with motivation to use and distribute self-tests for COVID-19 infection among US adults.

SARS-CoV-2 Screening Among Symptom-Free Healthcare Workers

Background

Transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is possible among symptom-free individuals and some patients are avoiding medically necessary healthcare visits for fear of becoming infected in the healthcare setting. Limited data are available on the point prevalence of SARS-CoV-2 infection in symptom-free U.S. healthcare workers (HCW).

Methods

A cross-sectional convenience sample of symptom-free HCWs from the metropolitan area surrounding Minneapolis and St. Paul, Minnesota was enrolled between April 20 ^th and June 24 ^th , 2020. A participant self-collected nasopharyngeal swab (NPS) was obtained. SARS-CoV-2 infection was assessed via polymerase chain reaction. Participants were queried about their willingness to repeat a self-collection NPS for diagnostic purposes. We had >95% power to detect at least one positive test if the true underlying prevalence of SARS-CoV2 was ≥1%.

Results

Among n=489 participants 80% were female and mean age±SD was 41±11. Participants reported being physicians (14%), nurse practitioners (8%), physician's assistants (4%), nurses (51%), medics (3%), or other which predominantly included laboratory technicians and administrative roles (22%). Exposure to a known/suspected COVID-19 case in the 14 days prior to enrollment was reported in 40% of participants. SARS-CoV-2 was not detected in any participant. Over 95% of participants reported a willingness to repeat a self-collected NP swab in the future.

Conclusions

The point prevalence of SARS-CoV-2 infection was likely <1% in a convenience sample of symptom-free Minnesota healthcare workers from April 20 ^th and June 24 ^th , 2020. Self-collected NP swabs are well-tolerated and a viable alternative to provider-collected swabs to preserve PPE.

Fully automated dried blood spot sample handling and extraction for serological testing of SARS-CoV-2 antibodies

At the beginning of 2020, an outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reached pandemic dimensions. Throughout the event, diagnostic tests function as an essential tool for understanding, mitigating, and implement strategies to curb and reduce infections. Here, we present a novel method for the fully automated dried blood spot (DBS) sample handling and extraction for serological testing of human IgG antibodies against SARS-CoV-2 using a commercial enzyme-linked immunosorbent assay (ELISA) testing kit. This proof-of-principle pilot study successfully demonstrates the recovery of antibodies in their intact form from DBS using automated, direct sample elution within 100 μl of extraction buffer. The use of minimally invasive DBS sampling provides an alternative to existing analytical procedures such as sampling by venipuncture or nasal swabs. Due to the ease of DBS collection, no third party need be involved, making at-home sampling possible (e.g., during quarantine).

Expanding Access to COVID-19 Tests through US Postal Service Facilities

Widespread, convenient access to COVID-19 testing has been challenging in the United States. We make a case for provisioning COVID-19 tests through the United States Postal Service (USPS) facilities and demonstrate a simple method for selecting locations to improve access. We provide quantitative evidence that even a subset of USPS facilities could provide broad access, particularly in remote and at-risk communities with limited access to health care. Based on daily travel surveys, census data, locations of USPS facilities, and an established care-seeking model, we estimate that more than 94% of the US population would be willing to travel to an existing USPS facility if warranted. For half of the US population, this would require traveling less than 2.5 miles from home; for 90%, the distance would be less than 7 miles. In Georgia, Illinois, and Minnesota, we estimate that testing at USPS facilities would provide access to an additional 4.1, 3.1, and 1.3 million people and reduce the median travel distance by 3.0, 0.8, and 1.2 miles, respectively, compared with existing testing sites per 28 July 2020. We also discuss the option of distributing test-at-home kits via USPS instead of private carriers. Finally, our proposal provides USPS an opportunity to increase revenues and expand its mission, thus improving its future prospects and relevance.

A comparison of health care worker-collected foam and polyester nasal swabs in convalescent COVID-19 patients

Both polyester and foam nasal swabs were collected from convalescent COVID-19 patients at a single visit and stored in viral transport media (VTM), saline or dry. Sensitivity of each swab material and media combination were estimated, three by three tables were constructed to measure polyester and foam concordance, and cycle threshold (Ct) values were compared. 126 visits had polyester and foam swabs stored in viral transport media (VTM), 51 had swabs stored in saline, and 63 had a foam swab in VTM and a polyester swab stored in a dry tube. Polyester and foam swabs had an estimated sensitivity of 87.3% and 94.5% respectively in VTM, 87.5% and 93.8% respectively in saline, and 75.0% and 90.6% respectively for dry polyester and foam VTM. Polyester and foam Ct values were correlated, but polyester showed decreased performance for cases with a viral load near the detection threshold and higher Ct values on average.

Self-Collected Anterior Nasal and Saliva Specimens versus Health Care Worker-Collected Nasopharyngeal Swabs for the Molecular Detection of SARS-CoV-2

We prospectively compared health care worker-collected nasopharyngeal swabs (NPS) to self-collected anterior nasal swabs (ANS) and straight saliva for the diagnosis of coronavirus disease 2019 (COVID-19) in 354 patients. The percent positive agreement between NPS and ANS or saliva was 86.3% (95% confidence interval [CI], 76.7 to 92.9%) and 93.8% (95% CI, 86.0 to 97.9%), respectively. The percent negative agreement was 99.6% (95% CI, 98.0 to 100.0%) for NPS versus ANS and 97.8% (95% CI, 95.3 to 99.2%) for NPS versus saliva. More cases were detected by the use of NPS (n = 80) and saliva (n = 81) than by the use of ANS (n = 70), but no single specimen type detected all severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections.

IFCC Interim Guidelines on Molecular Testing of SARS-CoV-2 Infection

The diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection globally has relied extensively on molecular testing, contributing vitally to case identification, isolation, contact tracing, and rationalization of infection control measures during the coronavirus disease 2019 (COVID-19) pandemic. Clinical laboratories have thus needed to verify newly developed molecular tests and increase testing capacity at an unprecedented rate. As the COVID-19 pandemic continues to pose a global health threat, laboratories continue to encounter challenges in the selection, verification, and interpretation of these tests. This document by the International Federation for Clinical Chemistry and Laboratory Medicine (IFCC) Task Force on COVID-19 provides interim guidance on: (A) clinical indications and target populations, (B) assay selection, (C) assay verification, and (D) test interpretation and limitations for molecular testing of SARS-CoV-2 infection. These evidence-based recommendations will provide practical guidance to clinical laboratories worldwide and highlight the continued importance of laboratory medicine in our collective pandemic response.

Self-Collected versus Healthcare Worker-Collected Swabs in the Diagnosis of Severe Acute Respiratory Syndrome Coronavirus 2

The aim of this study was to compare the sensitivity of self-collected versus healthcare worker (HCW)-collected swabs for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) testing. Symptomatic individuals referred for SARS-CoV-2 testing were invited to provide mobile-phone video-instructed self-collected oropharyngeal and nasal samples followed by a HCW-collected oropharyngeal sample. All samples were sent for analysis to the same microbiology laboratory, and the number of SARS-CoV-2-positive participants in the two tests was compared. A total of 109 participants were included, and 19 participants had SARS-CoV-2-positive results. The diagnostic sensitivity of the self-collected and HCW-collected swabs was 84.2% and 89.5%, respectively, with an acceptable agreement, Cohens kappa 0.82, p < 0.001. Further, results from a questionnaire answered by the participants found that loss of smell as a self-reported symptom was a strong predictor for a SARS-CoV-2-positive test. In conclusion, we found that self-collected oropharyngeal and nasal swabs for SARS-CoV-2 testing can be reliable compared to HCW-collected oropharyngeal samples.

Prevalence of Asymptomatic SARS-CoV-2 Infection in Children and Adults in Marion County, Indiana

BACKGROUND AND OBJECTIVES

Two community studies outside the US showed asymptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in adults, but not in children <10 years of age. In this study, we assessed the prevalence of asymptomatic SARS-CoV-2 infection in children and adults in Marion County, Indiana.

METHODS

Individuals living in Marion County with no symptoms of coronavirus 2019 disease (COVID-19) within seven days of enrollment were eligible for this cross-sectional household study. Study kits were delivered to the participant's residence for self-swabbing, picked up by the study team, and tested by polymerase chain reaction (PCR) for SAR-CoV-2 infection.

RESULTS

Five hundred eleven nasal swabs were collected from 119 children and 392 adults ≥18 years of age. One participant (seven years of age) tested positive, for an overall study prevalence of 0.2% (95% CI 0, 0.6%). The participant had no known contact with a person with SARS-CoV-2 infection, and five family members tested negative for infection. The child and family members all tested negative for infection 10 and 20 days after the first test, and none developed symptoms of COVID-19 for 20 days after testing.

CONCLUSIONS

Asymptomatic SARS-CoV-2 infection can occur in children <10 years with no known COVID-19 exposure. Large cohort studies should be conducted to determine prevalence of asymptomatic infection and risk of transmission from asymptomatic infection in children and adults over time.