Journal Article

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

Hill, Helen, Cheliotis, Katerina S., Davies, Kelly, Howard, Ashleigh, Nikolaou, Elissavet, Begier, Elizabeth, Todd, Stacy, Glynn, Sharon, Nastouli, Eleni, Farrar, Madlen, Beadsworth, Mike, Hitchins, Lisa, Cubas Atienzar, Ana I., Reiné, Jesús, Collins, Andrea M., Mitsi, Elena, Houlihan, Catherine F., Walker, Naomi F., Blandamer, Tess, Rashid-Gardner, Zalina, Byrne, Rachel L., Myerscough, Christopher, German, Esther L., Ferreira, Daniela M., Gessner, Bradford D., Solórzano, Carla, Adams, Emily R.

2023

Overview

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.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Asymptomatic / Biology and life sciences / Cohort analysis / Cohort Studies / Coronaviruses / COVID-19 / COVID-19 - diagnosis / Diagnostic tests / Disease transmission / Epidemics / Health care / Health Personnel / Health services / High temperature / Humans / Infections / Laboratories / Medical personnel / Medical screening / Medicine and health sciences / Methods / Nasopharynx / Observational studies / Pandemics / People and Places / Prevention / Retrospective Studies / Saliva / Salivary diagnostics / Sampling / SARS-CoV-2 / Severe acute respiratory syndrome coronavirus 2 / Specimen Handling / State Medicine / Surveillance / Viral diseases