SARS-CoV-2, the virus responsible for COVID-19, can persist in the blood and tissue of some patients for up to two years post-infection, offering new insights into the phenomenon of long COVID. This groundbreaking research found COVID antigens in blood samples up to 14 months after infection and in tissue samples for more than two years.
These findings suggest a possible explanation for the persistent and diverse symptoms experienced by long COVID sufferers and pave the way for clinical trials testing treatments aimed at eliminating the lingering virus to improve patient outcomes.
COVID-19 virus can persist in the blood and tissue of patients for more than a year after the acute phase of the illness has ended, according to new research from UC San Francisco that offers potential clues to why some people develop long COVID.
The scientists found pieces of SARS-CoV-2, referred to as COVID antigens, lingering in the blood up to 14 months after infection and for more than two years in tissue samples from people who had COVID.
These two studies provide some of the strongest evidence so far that COVID antigens can persist in some people, even though we think they have normal immune responses, said Michael Peluso, MD, an infectious disease researcher in the UCSF School of Medicine, who led both studies.
The findings were presented at the Conference on Retroviruses and Opportunistic Infections, which was held in Denver.
Early in the pandemic, COVID-19 was thought to be a transient illness. But a growing number of patients, even those who had previously been healthy, continued having symptoms, such as brain fog, digestive problems, and vascular issues, for months or even years.
The researchers looked at blood samples from 171 people who had been infected with COVID. Using an ultra-sensitive test for the COVID spike protein, which helps the virus break into human cells, the scientists found the virus was still present up to 14 months later in some people.
Since the virus is believed to persist in the tissue reservoirs, the scientists turned to UCSF’s Long COVID Tissue Bank, which contains samples donated by patients with and without long COVID. They detected portions of viral RNA for up to two years after infection, although there was no evidence that the person had become reinfected.
Peluso said more research is needed to determine whether the persistence of these fragments drives long COVID and associated risks such as heart attack and stroke. But his team at UCSF is involved in clinical trials testing whether monoclonal antibodies or antiviral drugs can remove the virus and improve the health of people with long COVID.
There is a lot more work to be done, but I feel like we are making progress in really understanding the long-term consequences of this infection, Peluso said.
