A combined oropharyngeal/nares swab is a suitable alternative to nasopharyngeal swabs for the detection of SARS-CoV-2

LeBlanc, Jason J.; Heinstein, Charles; Macdonald, J.D.; Pettipas, Janice; Hatchette, Todd F.; Patriquin, Glenn

doi:10.1016/j.jcv.2020.104442

Cited by 80 publications

(117 citation statements)

References 12 publications

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“…Additional testing would have allowed more objective tracking of transmission and diagnosis in pre-symptomatic residents and staff, while testing for other viruses may have explained the development of new symptoms in SARS/CoV-2 positive and negative residents and staff. Moreover, SARS-CoV-2 testing detection could have been improved by testing multiple sites, such as the nose and throat [24], and repeated testing, but this was impractical in our cohort. We also only tested staff who were working at the care home at the time of the investigation and, therefore, may have missed testing those who were symptomatic and self-isolating at home.…”

Section: Discussionmentioning

confidence: 99%

Investigation of SARS-CoV-2 outbreaks in six care homes in London, April 2020

et al. 2020

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Background: Care homes are experiencing large outbreaks of COVID-19 associated with high case-fatality rates. We conducted detailed investigations in six London care homes reporting suspected COVID-19 outbreaks during April 2020. Methods: Residents and staff had nasal swabs for SARS CoV-2 testing using RT-PCR and were followed-up for 14 days. They were categorized as symptomatic, post-symptomatic or pre-symptomatic if they had symptoms at the time of testing, in the two weeks before or two weeks after testing, respectively, or asymptomatic throughout. Virus isolation and whole genome sequencing (WGS) was also performed. Findings: Across the six care homes, 105/264 (39.8%) residents were SARS CoV-2 positive, including 28 (26.7%) symptomatic, 10 (9.5%) post-symptomatic, 21 (20.0%) pre-symptomatic and 46 (43.8%) who remained asymptomatic. Case-fatality at 14-day follow-up was highest among symptomatic SARS-CoV-2 positive residents (10/28, 35.7%) compared to asymptomatic (2/46, 4.3%), post-symptomatic (2/10, 20.0%) or pre-symptomatic (3/21,14.3%) residents. Among staff, 53/254 (20.9%) were SARS-CoV-2 positive and 26/53 (49.1%) remained asymptomatic. RT-PCR cycle-thresholds and live-virus recovery were similar between symptomatic/asymptomatic residents/staff. Higher RT-PCR cycle threshold values (lower virus load) samples were associated with exponentially decreasing ability to recover infectious virus (P<0.001). WGS identified multiple (up to 9) separate introductions of different SARS-CoV-2 strains into individual care homes. Interpretation: A high prevalence of SARS-CoV-2 positivity was found in care homes residents and staff, half of whom were asymptomatic and potential reservoirs for ongoing transmission. A third of symptomatic SARS-CoV-2 residents died within 14 days. Symptom-based screening alone is not sufficient for outbreak control.

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Section: Discussionmentioning

confidence: 99%

Investigation of SARS-CoV-2 outbreaks in six care homes in London, April 2020

et al. 2020

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“…(2) Specifically, the shortage in nasopharyngeal swabs (NPS), the standard specimen collection device for the diagnosis of respiratory viral infections, has necessitated the investigation and employment of nasal mid-turbinate swabs, anterior nares swabs and even saliva as alternate specimens for the diagnosis of COVID -19 infection. (3)(4)(5) Several studies have investigated the use of saliva as a specimen for testing for SARS-CoV-2 with mixed results. (3,(5)(6)(7)(8)(9)(10)(11) We, therefore, undertook a direct NPS to saliva specimen comparison to provide further clarification regarding the use of saliva as a potential specimen for testing.…”

Section: Introductionmentioning

confidence: 99%

A Direct Comparison of Enhanced Saliva to Nasopharyngeal Swab for the Detection of SARS-CoV-2 in Symptomatic Patients

et al. 2020

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Background: The ongoing COVID-19 pandemic has resulted in shortages in nasopharyngeal swabs (NPS) and viral transport media, necessitating the search for alternate diagnostic specimens, such as saliva. We directly compared matched saliva and NPS specimens from symptomatic patients suspected of having COVID-19. Methods: An enhanced saliva specimen (ie strong sniff, elicited cough, and collection of saliva/secretions) was collected without transport media prior to NPS from 224 patients with symptoms deemed consistent with COVID-19. Both specimens were tested with the CDC 2019 nCoV Real-Time RT-PCR Diagnostic Panel (4 February 2020 version), with the NPS result used as the reference standard. Results: Of the 216 patients included in the final analysis, there was a 100% Positive Percent Agreement (38/38 positive specimens) and 99.4% Negative Percent Agreement (177/178 negative specimens). The one discrepant specimen had the presence of SARS-CoV-2 confirmed in the saliva specimen using an alternate FDA EUA assay. The overall mean difference in crossing threshold (Ct) values for the positive NPS and saliva specimens was -3.61 (95% C.I. -5.78 to -1.44, p = 0.002). Conclusion: An enhanced saliva specimen performed as well as NPS for the qualitative detection of SARS-CoV-2 in symptomatic patients, albeit the overall mean viral load in saliva was lower.

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“…Each dot represents one of the 27 patients who had positive OPS and NPS. The trend line is estimated by a simple linear regression of clinical sensitivity [14,15]. NW have also yielded promising upper respiratory virus detection rates [12,16].…”

Section: Discussionmentioning

confidence: 99%

Sensitivity of nasopharyngeal, oropharyngeal, and nasal wash specimens for SARS-CoV-2 detection in the setting of sampling device shortage

Calame

Mazza

Renzoni

et al. 2020

Eur J Clin Microbiol Infect Dis

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In the context of an unprecedented shortage of nasopharyngeal swabs (NPS) or sample transport media during the coronavirus disease 2019 (COVID-19) crisis, alternative methods for sample collection are needed. To address this need, we validated a cell culture medium as a viral transport medium, and compared the analytical sensitivity of SARS-CoV-2 RT-PCR in nasal wash (NW), oropharyngeal swab (OPS), and NPS specimens. Both the clinical and analytical sensitivity were comparable in these three sample types. OPS and NW specimens may therefore represent suitable alternatives to NPS for SARS-CoV-2 detection.

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A combined oropharyngeal/nares swab is a suitable alternative to nasopharyngeal swabs for the detection of SARS-CoV-2

Cited by 80 publications

References 12 publications

Investigation of SARS-CoV-2 outbreaks in six care homes in London, April 2020

Investigation of SARS-CoV-2 outbreaks in six care homes in London, April 2020

A Direct Comparison of Enhanced Saliva to Nasopharyngeal Swab for the Detection of SARS-CoV-2 in Symptomatic Patients

Sensitivity of nasopharyngeal, oropharyngeal, and nasal wash specimens for SARS-CoV-2 detection in the setting of sampling device shortage

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