Discriminatory ability of gas chromatography-ion mobility spectrometry to identify patients hospitalised with COVID-19 and predict prognosis (preprint)

Background Tests that can diagnose COVID-19 rapidly and predict prognosis would be significantly beneficial. We studied the ability of breath analysis using gas chromatography-ion mobility spectrometry (GC-IMS) for diagnosis of COVID-19 and as a predictor for subsequent requirement for Continuous Positive Airway Pressure (CPAP). Methods We undertook a single centre prospective observational study in patients with COVID-19, other respiratory tract infections and healthy controls. Participants provided one breath sample for GC-IMS analysis. We used cross validation analysis to create models that were then tested against the original cohort data. Further multivariable analysis was undertaken to adjust for differences between the comparator groups. Results Between 01/02/2021 and 24/05/2021 we recruited 113 participants, of whom 72 (64%) had COVID-19, 20 (18%) had another respiratory tract infection and 21 (19%) were healthy controls. Differentiation between patients with COVID-19 and healthy controls, and patients with COVID-19 and those with other respiratory tract infections, was achieved with high accuracy. Identification of patients with subsequent requirement for CPAP was completed with moderate accuracy and was not independently associated on multivariable analysis. Conclusions We have shown that GC-IMS has a high capability to distinguish between acute COVID-19 infection and other disease states. Breath analysis shows promise as a predictor of subsequent requirement for CPAP in hospitalised patients with COVID-19. This platform has considerable benefits due to the test being rapid, non-invasive and not requiring specialist laboratory processing.

Quantification and prognostic significance of interferon-γ secreting SARS-CoV-2 responsive T cells in hospitalised patients with acute COVID-19 (preprint)

Little is known about T-cell responses during acute coronavirus disease-2019 (COVID-19). We measured T-cell interferon gamma (IFN-{gamma}) responses to spike 1 (S1), spike 2 (S2), nucleocapsid (N) and membrane (M) SARS-CoV-2 antigens using the T-SPOT(R) Discovery SARS-CoV-2 assay, a proven EliSPOT technology, in 114 hospitalised adult COVID-19 patients and assessed their association with clinical disease phenotype. T-SPOT(R) Discovery SARS-CoV-2 responses were detectable within 2 days of a positive PCR and did not correlate with vaccination status or symptom duration. Higher responses to S1 protein associated with a higher symptom burden, and serum IL-6 levels. Despite treatment with dexamethasone this subgroup was also at greater risk of requiring continuous positive airway pressure (CPAP) in the days following sampling. Higher T-cell responses measured using T-SPOT(R) Discovery SARS-CoV-2 associate with progressive disease in acute COVID-19 disease and may have utility as a prognostic biomarker that should be evaluated in larger cohorts.