The 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 (CROI), which was held March 3 to 6, 2024, in Denver.
Evidence of long-term infection
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.
Among those who were hospitalized for COVID, the likelihood of detecting the COVID antigens was about twice as high as it was for those who were not. It was also higher for those who reported being sicker, but were not hospitalized.
“As a clinician, these associations convince me that we are on to something, because it makes sense that someone who had been sicker with COVID would have more antigen that can stick around,” Peluso said.
Virus persists for up to two years in tissue
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. They found it in the connective tissue where immune cells are located, suggesting that the viral fragments were causing the immune system to attack. In some of the samples, the researchers found that the virus could be active.
Peluso said more research is needed to determine whether the persistence of these fragments drives long COVID and such associated risks as heart attack and stroke.
But, based on these findings, Peluso’s team at UCSF is involved in multiple clinical trials that are 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.
Meeting: Conference on Retroviruses and Opportunistic Infections (CROI)
The studies were supported by funding from the PolyBio Research Foundation to support UCSF’s Long-Term Impact of Infection with Novel Coronavirus (LIINC) Clinical Core and a Merck Investigator Studies Program Grant. The National Institute of Health’s National Institute of Allergy and Infectious Diseases also provided funding (3R01AI1411003-03S1, R01AI158013 and K23AI134327, K23AI157875 and K24AI145806). Additional support came from the Zuckerberg San Francisco General Hospital Department of Medicine and Division of HIV, Infectious Diseases and Global Medicine.
![](https://www.nanoappsmedical.com/wp-content/uploads/2017/05/spacer.jpg)
News
The Silent Battle Within: How Your Organs Choose Between Mom and Dad’s Genes
Research reveals that selective expression of maternal or paternal X chromosomes varies by organ, driven by cellular competition. A new study published today (July 26) in Nature Genetics by the Lymphoid Development Group at the MRC [...]
Study identifies genes increasing risk of severe COVID-19
Whether or not a person becomes seriously ill with COVID-19 depends, among other things, on genetic factors. With this in mind, researchers from the University Hospital Bonn (UKB) and the University of Bonn, in [...]
Small regions of the brain can take micro-naps while the rest of the brain is awake and vice versa
Sleep and wake: They're totally distinct states of being that define the boundaries of our daily lives. For years, scientists have measured the difference between these instinctual brain processes by observing brain waves, with [...]
Redefining Consciousness: Small Regions of the Brain Can Take Micro-Naps While the Rest of the Brain Is Awake
The study broadly reveals how fast brain waves, previously overlooked, establish fundamental patterns of sleep and wakefulness. Scientists have developed a new method to analyze sleep and wake states by detecting ultra-fast neuronal activity [...]
AI Reveals Health Secrets Through Facial Temperature Mapping
Researchers have found that different facial temperatures correlate with chronic illnesses like diabetes and high blood pressure, and these can be detected using AI with thermal cameras. They highlight the potential of this technology [...]
Breakthrough in aging research: Blocking IL-11 extends lifespan and improves health in mice
In a recent study published in the journal Nature, a team of researchers used murine models and various pharmacological and genetic approaches to examine whether pro-inflammatory signaling involving interleukin (IL)-11, which activates signaling molecules such [...]
Promise for a universal influenza vaccine: Scientists validate theory using 1918 flu virus
New research led by Oregon Health & Science University reveals a promising approach to developing a universal influenza vaccine—a so-called "one and done" vaccine that confers lifetime immunity against an evolving virus. The study, [...]
New Projects Aim To Pioneer the Future of Neuroscience
One study will investigate the alterations in brain activity at the cellular level caused by psilocybin, the psychoactive substance found in “magic mushrooms.” How do neurons respond to the effects of magic mushrooms? What [...]
Decoding the Decline: Scientific Insights Into Long COVID’s Retreat
Research indicates a significant reduction in long COVID risk, largely due to vaccination and the virus’s evolution. The study analyzes data from over 441,000 veterans, showing lower rates of long COVID among vaccinated individuals compared [...]
Silicon Transformed: A Breakthrough in Laser Nanofabrication
A new method enables precise nanofabrication inside silicon using spatial light modulation and laser pulses, creating advanced nanostructures for potential use in electronics and photonics. Silicon, the cornerstone of modern electronics, photovoltaics, and photonics, [...]
Caught in the actinium: New research could help design better cancer treatments
The element actinium was first discovered at the turn of the 20th century, but even now, nearly 125 years later, researchers still don't have a good grasp on the metal's chemistry. That's because actinium [...]
Innovative Light-Controlled Drugs Could Revolutionize Neuropathic Pain Treatment
A team of researchers from the Institute for Bioengineering of Catalonia (IBEC) has developed light-activated derivatives of the anti-epileptic drug carbamazepine to treat neuropathic pain. Light can be harnessed to target drugs to specific [...]
Green Gold: Turning E-Waste Into a Treasure Trove of Rare Earth Metals
Scientists are developing a process inspired by nature that efficiently recovers europium from old fluorescent lamps. The approach could lead to the long-awaited recycling of rare earth metals. A small molecule that naturally serves [...]
Cambridge Study: AI Chatbots Have an “Empathy Gap,” and It Could Be Dangerous
A new study suggests a framework for “Child Safe AI” in response to recent incidents showing that many children perceive chatbots as quasi-human and reliable. A study has indicated that AI chatbots often exhibit [...]
Nanoparticle-based delivery system could offer treatment for diabetics with rare insulin allergy
Up to 3% of people with diabetes have an allergic reaction to insulin. A team at Forschungszentrum Jülich has now studied a method that could be used to deliver the active substance into the [...]
Nanorobot kills cancer cells in mice with hidden weapon
Researchers at Karolinska Institutet in Sweden have developed nanorobots that kill cancer cells in mice. The robot's weapon is hidden in a nanostructure and is exposed only in the tumor microenvironment, sparing healthy cells. [...]