Some long COVID patients still have virus in blood
27/06 - Some cases of long COVID may be the immune system's response to a SARS-CoV-2 infection lurking somewhere in the body, new findings from a small study suggest.
Researchers analyzed multiple plasma samples collected over time from 63 patients with COVID-19, including 37 who went on to develop long COVID. In the majority of those with long COVID, the spike protein from the surface of the virus was detectable for up to 12 months, whereas it was not present in plasma samples from recovered patients without lasting symptoms. Spike protein circulating in the blood could mean "a reservoir of active virus persists in the body," the researchers said in a paper posted on medRxiv ahead of peer review.
Exactly where that reservoir might be is not clear from this study. Researchers said they have previously found active virus in the gastrointestinal tract of children weeks after the initial coronavirus infection, and other researchers have found genetic evidence of the virus "in multiple anatomic sites up to seven months after symptom onset."
If the results can be confirmed in larger studies, the presence of spike protein in the blood long after the initial infection may be one way to diagnose long COVID, the researchers said.