Deliberate infection trial found COVID symptoms do not indicate viral precipitation

A 3D-printed model of the coronavirus appears in front of the phrase Coronavirus disease (COVID-19) displayed in this illustration taken on March 25, 2020. REUTERS / Dado Ruvic / Illustration / File Photo

April 1 (Reuters) – The world’s first “human challenge” trial in which volunteers were deliberately exposed to the coronavirus found that symptoms had no effect on how likely an infected person was to transmit the disease to others.

The findings underscore the difficulty of preventing community infection as the World Health Organization (WHO) warns that cases are on the rise.

Research project managed by Open Orphan (ORPH.L) With Imperial College, London, that of the 18 participants who contracted COVID-19, the severity of symptoms, or whether they developed symptoms at all, was unrelated to viral load in the airways. Read more

Viral load, or propensity to shed virus, was measured by two methods known as foci formation assay (FFA) and quantitative polymerase chain reaction (qPCR).

“There was no association between the amount of virus precipitation by qPCR or FFA and the degree of symptoms,” the researchers said in a research paper published in the scientific journal Nature Medicine.

The imperial trial exposed 36 healthy adults without a history of infection or vaccination against the original SARS-CoV-2 strain of the virus and monitored them in quarantine. Read more

Since two of the volunteers were found to have antibodies to the virus after all, they were excluded from the analysis. Just over half of them contracted the virus.

No serious adverse events have occurred, the research team said earlier this year, and the human challenge study model has been shown to be safe and well-tolerated in healthy adults.

Ludwig Burger reports. Editing by Robert Persell

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