In a groundbreaking study conducted by researchers at UC San Francisco, it has been discovered that SARS-CoV-2, the virus responsible for COVID-19, can persist in the blood and tissue of some individuals for an extended period of time. These findings offer new insights into the phenomenon of long COVID and provide a possible explanation for the persistent and diverse symptoms experienced by long COVID sufferers.

The research, presented at the Conference on Retroviruses and Opportunistic Infections, examined blood samples from 171 individuals who had been infected with COVID-19. Using an ultra-sensitive test for COVID antigens, the scientists detected fragments of the virus, known as COVID antigens, up to 14 months after the initial infection in some patients. Additionally, in tissue samples from individuals who had COVID, viral RNA was found to persist for more than two years, indicating the presence of the virus in tissue reservoirs.

The likelihood of detecting COVID antigens was found to be higher in individuals who experienced severe illness and those who were hospitalized for COVID. This suggests a correlation between the persistence of the virus and the severity of the initial infection. The study also found evidence that the viral fragments were causing the immune system to trigger attacks on the connective tissue where the fragments were present.

"These 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 Dr. Michael Peluso, the lead researcher.

The implications of these findings are significant for long COVID research. The persistence of COVID antigens in the blood and tissue may play a role in driving long-term symptoms experienced by some individuals. Based on these findings, Dr. Peluso and his team at UCSF are now involved in multiple clinical trials testing treatments aimed at eliminating the lingering virus to improve patient outcomes.

"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," said Dr. Peluso.

The research was supported by funding from the PolyBio Research Foundation and the Merck Investigator Studies Program Grant, as well as the National Institute of Health's National Institute of Allergy and Infectious Diseases. The findings underscore the importance of ongoing research and clinical trials to address the long-term effects of COVID-19 and develop effective treatments for long COVID patients.

As the understanding of the long-term impact of the COVID-19 infection continues to evolve, these new findings provide hope for improved outcomes and management strategies for individuals suffering from long COVID.