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Detection of SARS-CoV-2 infection by saliva and nasopharyngeal sampling in frontline healthcare workers: An observational cohort study

Walker, Naomi ORCID:, Byrne, Rachel, Howard, Ashleigh, Nikolaou, Elissavet, Farrar, Madi, Glynn, Sharon, Cheliotis, Katerina, CubasAtienzar, Ana, Davies, Kelly, Reiné, Jesús, Rashid-Gardner, Zalina, German, Esther, SolorzanoGonzalez, Carla, Blandamer, Tess, Hitchins, Lisa, Myerscough, Christopher, Gessner, Bradford D., Begier, Elizabeth, Collins, Andrea ORCID:, Beadsworth, Mike, Todd, Stacy, Hill, Helen, Houlihan, Catherine F., Nastouli, Eleni, Adams, Emily ORCID:, Mitsi, Elena and Ferreira, Daniela ORCID: (2023) 'Detection of SARS-CoV-2 infection by saliva and nasopharyngeal sampling in frontline healthcare workers: An observational cohort study'. PLoS ONE, Vol 18, Issue 1, e0280908.

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The SARS-CoV-2 pandemic has caused an unprecedented strain on healthcare systems worldwide, including the United Kingdom National Health Service (NHS). We conducted an observational cohort study of SARS-CoV-2 infection in frontline healthcare workers (HCW) working in an acute NHS Trust during the first wave of the pandemic, to answer emerging questions surrounding SARS-CoV-2 infection, diagnosis, transmission and control.


Using self-collected weekly saliva and twice weekly combined oropharyngeal/nasopharyngeal (OP/NP) samples, in addition to self-assessed symptom profiles and isolation behaviours, we retrospectively compared SARS-CoV-2 detection by RT-qPCR of saliva and OP/NP samples. We report the association with contemporaneous symptoms and isolation behaviour.


Over a 12-week period from 30th March 2020, 40·0% (n = 34/85, 95% confidence interval 31·3–51·8%) HCW had evidence of SARS-CoV-2 infection by surveillance OP/NP swab and/or saliva sample. Symptoms were reported by 47·1% (n = 40) and self-isolation by 25·9% (n = 22) participants. Only 44.1% (n = 15/34) participants with SARS-CoV-2 infection reported any symptoms within 14 days of a positive result and only 29·4% (n = 10/34) reported self-isolation periods. Overall agreement between paired saliva and OP/NP swabs was 93·4% (n = 211/226 pairs) but rates of positive concordance were low. In paired samples with at least one positive result, 35·0% (n = 7/20) were positive exclusively by OP/NP swab, 40·0% (n = 8/20) exclusively by saliva and in only 25·0% (n = 5/20) were the OP/NP and saliva result both positive.


HCW are a potential source of SARS-CoV-2 transmission in hospitals and symptom screening will identify the minority of infections. Without routine asymptomatic SARS-CoV-2 screening, it is likely that HCW with SARS-CoV-2 infection would continue to attend work. Saliva, in addition to OP/NP swab testing, facilitated ascertainment of symptomatic and asymptomatic SARS-CoV-2 infections. Combined saliva and OP/NP swab sampling would improve detection of SARS-CoV-2 for surveillance and is recommended for a high sensitivity strategy

Item Type: Article
Corporate Authors: on behalf of the SAFER investigators
Subjects: W General Medicine. Health Professions > W 21.5 Allied health personnel. Allied health professions
QY Clinical Pathology > Diagnostic Tests > QY 125 Saliva
WA Public Health > WA 20.5 Research (General)
WC Communicable Diseases > WC 20 Research (General)
WC Communicable Diseases > Virus Diseases > Viral Respiratory Tract Infections. Respirovirus Infections > WC 506 COVID-19
Faculty: Department: Biological Sciences > Department of Tropical Disease Biology
Clinical Sciences & International Health > Clinical Sciences Department
Digital Object Identifer (DOI):
SWORD Depositor: JISC Pubrouter
Depositing User: JISC Pubrouter
Date Deposited: 02 Feb 2023 13:37
Last Modified: 02 Feb 2023 13:37


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