Antiviral metabolite 3'-Deoxy-3',4'-didehydro-cytidine is detectable in serum and identifies acute viral infections including COVID-19 (preprint)

There is a critical need for improved infectious disease diagnostics to enable rapid case identification in a viral pandemic and support targeted antimicrobial prescribing. Here we use high-resolution liquid chromatography coupled with mass spectrometry to compare the admission serum metabolome of patients attending hospital with a range of viral infections, including SARS-CoV-2, to those with bacterial infections, non-infected inflammatory conditions and healthy controls. We demonstrate for the first time that 3'-Deoxy-3',4'-didehydro-cytidine (ddhC), a free base of the only known human antiviral small molecule ddhC-triphosphate (ddhCTP), is detectable in serum. ddhC acts as an accurate biomarker for viral infections, generating an area under the receiver operating characteristic curve of 0.954 (95% confidence interval 0.923-0.986) when comparing viral to non-viral cases. Gene expression of viperin, the enzyme responsible for ddhCTP synthesis, is highly correlated with ddhC, providing a biological mechanism for its increase during viral infection. These findings underline a key future diagnostic role of ddhC in the context of pandemic preparedness and antimicrobial stewardship.

Rapid detection of SARS-CoV2 by Ambient Mass Spectrometry Techniques (preprint)

Ambient Ionisation Mass Spectrometry techniques: Desorption Electrospray Ionisation (DESI) and Laser Desorption Rapid Evaporative Ionisation Mass Spectrometry (LD-REIMS) were used to detect the SARS-CoV-2 in dry nasal swabs. 45 patients were studied from samples collected between April & June 2020 in a clinical feasibility study. Diagnostic accuracy was calculated as 86.7% and 84% for DESI and LD-REIMS respectively. Results can be acquired in seconds providing robust and quick analysis of COVID-19 status which could be carried out without the need for a centralised laboratory. This technology has the potential to provide an alternative to population testing and enable the track and trace objectives set by governments and curtail the effects of a second surge in COVID-19 positive cases. In contrast to current PCR testing, using this technique there is no requirement of specific reagents which can cause devastating delays upon breakdowns of supply chains, thus providing a promising alternative testing method.