Is the extent of circulating SARS-CoV-2 RNA or spike protein related to acute illness severity?

In a current research posted to the medRxiv* preprint server, researchers investigated the degrees of circulating extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein and viral ribonucleic acid (RNA) amongst sufferers hospitalized with acute coronavirus illness 2019 (COVID-19) and in sufferers with and with out post-acute sequelae of COVID-19 (PASC).

Study: Persistent Presence of Spike protein and Viral RNA in the Circulation of Individuals with Post-Acute Sequelae of COVID-19. Image Credit: Dotted Yeti/Shutterstock
Examine: Persistent Presence of Spike protein and Viral RNA in the Circulation of Individuals with Post-Acute Sequelae of COVID-19. Picture Credit score: Dotted Yeti/Shutterstock


Appreciable analysis progress pertaining to acute COVID-19 manifestations has occurred; nevertheless, PASC knowledge are missing. It’s important to elucidate the underlying mechanisms of PASC pathophysiology for figuring out people most liable to develop PASC and for investigating targets for the event of potential anti-SARS-CoV-2 medication.

In regards to the research

Within the current research, researchers investigated if the circulation of SARS-CoV-2 S or RNA was related to the severity of acute COVID-19 and if the persistence of the viral parts correlated with PASC manifestations.

The degrees of SARS-CoV-2 S and RNA in plasma obtained from 151 acute COVID-19 (n=116, symptomatic and hospitalized) or PASC sufferers have been analyzed, and their COVID-19 analysis was confirmed by polymerase chain response (PCR) exams. The acute COVID-19 sufferers have been categorized on the premise of their World Well being Group (WHO) illness severity/scientific development scores as (i) reasonable COVID-19 with out oxygen (O2) necessities (n=39), (ii) reasonable COVID-19 requiring oxygen supplementation (n=40), and (iii) extreme COVID-19 (n=37).

People have been thought of to be PASC sufferers in the event that they skilled ≥1 COVID-19 symptom for >8 weeks post-COVID-19 analysis. As well as, 12 sufferers of the acute COVID biorepository have been included within the evaluation. Samples from the acute COVID-19 group have been obtained on the preliminary day of enrollment and each three days till hospital discharge or loss of life.

PASC group samples have been obtained on the day of recruitment ≥18 weeks post-acute COVID-19 interval. SARS-CoV-2 RNA extracted from the samples was evaluated by reverse-transcription-droplet digital PCR (RT-ddPCR) exams. Plasma-derived small extracellular vesicles (SEVs) have been remoted and analyzed, and SARS-CoV-2 S and SEV ranges have been measured by enzyme-linked immunosorbent assays (ELISA).

Knowledge on demographics, comorbidities, physique mass index (BMI), COVID-19 symptoms, and the length between the newest SARS-CoV-2-positive report and research recruitment have been obtained from REDCap surveys and/or digital medical data. The surveys have been performed at recruitment and three-monthly utilizing WHO’s post-COVID situations case report type (post-COVID-19 CRF).


Amongst hospitalized sufferers with acute SARS-CoV-2 infections, optimistic correlations have been noticed for SARS-CoV-2 S and D-dimer, hospitalization length, and WHO peak scores and between SARS-CoV-2 RNA ranges and LDH (lactate dehydrogenase, tissue injury biomarker) ranges. The comparability of 33 PASC sufferers with post-COVID-19 signs (PASC-positive) and 14 PASC-negative sufferers confirmed a higher chance of SARS-CoV-2 and viral RNA presence amongst PASC sufferers (with significantly greater ranges in just a few instances) compared to sufferers with acute SARS-COV-2 infections.

SARS-CoV-2 RNA positivity was greater amongst PASC sufferers with acute SARS-CoV-2 infections, whereas SARS-CoV-2 S was comparable between the 2 teams. As well as, some SARS-CoV-2 S proteins have been linked to EVs with out SARS-CoV-2 RNA in vesicles. SARS-CoV-2 RNA was present in 33%, 35%, and 37% of sufferers with reasonable COVID-19 with out O2 wants, reasonable COVID-19 with O2 want, and extreme COVID-19, respectively, with out considerably totally different ranges among the many teams.

The corresponding percentages for the three teams for SARS-CoV-2 S presence have been 51%, 68%, and 68%, respectively. About 45%, 37%, and 50% of SARS-CoV-2 S-positive samples of the corresponding teams confirmed SARS-CoV-2 S in EVs. SARS-CoV-2 RNA ranges correlated considerably with BMI values amongst sufferers with extreme COVID-19.

The general positivity for SARS-CoV-2 RNA and S protein have been 35% and 62%, respectively, amongst symptomatic acute COVID-19 sufferers. About 34% and 6% of the acute COVID-19 group sufferers have been optimistic for under SARS-CoV-2 S and solely SARS-CoV-2 RNA solely. PASC signs have been extra more likely to develop amongst ladies with respiratory comorbidities reminiscent of obstructive sleep apnea or bronchial asthma.

PASC-negative sufferers have been extra more likely to endure from diabetes, renal illnesses, and coronary artery illnesses and had greater odds of being hospitalized as a consequence of acute COVID-19. SARS-CoV-2 RNA was current in 28% of PASC-negative sufferers (copy numbers between 0.1 to 2.1 copies/ul) and amongst 59% of PASC-positive sufferers (copy numbers between 0.1 and 12.7 copies/ul).

SARS-CoV-2 S was current in 14 and 21 PASC-negative and PASC-positive sufferers, respectively. Amongst PASC-positive sufferers, 33% (n=11) samples have been SARS-CoV-2 S- and viral RNA-positive, 30% (n=10) have been optimistic for SARS-CoV-2 S solely and 18% (n=6) for SARS-CoV-2 RNA solely. Nevertheless, not one of the PASC-negative sufferers have been optimistic for each the viral parts. Additional, 53% (n=8) of PASC-positive sufferers confirmed positivity for EV-linked S, and the degrees have been much like these present in acute COVID-19 sufferers, whereas EVs amongst PASC-negative sufferers have been SARS-CoV-2 S-negative.


Total, the research findings demonstrated the persistence of circulating SARS-CoV-2 S and RNA fragments amongst PASC sufferers (>1 yr of COVID-19 analysis in just a few instances), regardless of their absence or presence within the acute part of COVID-19. The findings additionally confirmed that SARS-CoV-2 S however not RNA was current in SEVs of plasma obtained from acute COVID-19 or lengthy COVID sufferers.

*Essential discover

medRxiv publishes preliminary scientific experiences that aren’t peer-reviewed and, due to this fact, shouldn’t be considered conclusive, information scientific follow/health-related habits, or handled as established data.

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