Long COVID, affecting 5-10% of COVID-19 patients, might be caused by the enduring presence of the virus in the body.
Research suggests that viral fragments, possibly live, linger and lead to symptoms. Addressing this involves antiviral treatments, enhanced public awareness, and preventive measures against reinfection.
Understanding Long COVID and Its Prevalence
About 5–10% of people infected with COVID-19 develop long COVID, experiencing symptoms that last three months or longer.
Scientists have suggested several biological mechanisms to explain long COVID. However, in a recent perspective article in the Medical Journal of Australia, we propose that long COVID may largely be caused by the virus itself persisting in the body.
Since the early days of the pandemic, researchers have recognized that SARS-CoV-2 — or its remnants — can remain in different tissues and organs long after the initial infection. This phenomenon is referred to as “viral persistence.”
Credit: SciTechDaily.com
Evidence of Persistent Virus and Its Implications
While the long-term presence of residual viral fragments in some people’s bodies is now well established, what remains less certain is whether live virus itself, not just old bits of virus, is lingering – and if so, whether this is what causes long COVID. This distinction is crucial because live virus can be targeted by specific antiviral approaches in ways that “dead” viral fragments cannot.
Viral persistence has two significant implications:
- when it occurs in some highly immunocompromised people, it is thought to be the source of new and substantially different-looking variants, such as JN.1
- it has the potential to continue to cause symptoms in many people in the wider population long beyond the acute illness. In other words, long COVID could be caused by a long infection.
Current Research Findings on Viral Persistence
While there remains no single study that confirms that persistent virus is the cause of long COVID, collectively several recent key papers make a compelling case.
In February, a study in Nature found a high number of people with mild COVID symptoms had extended periods of shedding the genetic material of the virus, so-called viral RNA, from their respiratory tract. Those with persistent shedding of this viral RNA – which almost certainly represents the presence of live virus – were at higher risk of long COVID.
Other key papers detected replicating viral RNA and proteins in blood fluid of patients years after their initial infection, a sign that the virus is likely replicating for long periods in some hidden reservoirs in the body, perhaps including blood cells.
Another study detected viral RNA in ten different tissue sites and blood samples 1–4 months after acute infection. This study found the risk of long COVID (measured four months following infection) was higher in those with persistently positive viral RNA.
The same study also gave clues about where in the body the persisting virus resides. The gastrointestinal tract is one site of considerable interest as a long-term viral hideout.
The Challenge of Proving Viral Replication
Earlier this month, further evidence of persistent virus increasing likelihood of long COVID has been published as part of the RECOVER initiative, a collaborative research project that aims to address the impacts of long COVID.
However, formal proof that virus capable of replicating can last for years in the body remains elusive. This is because isolating the live virus from reservoirs inside the body where the virus “hides” is technically challenging.
In its absence, we and other scientists argue the cumulative evidence is now sufficiently compelling to galvanise action.
Strategies to Address Long COVID
The obvious response to this is to fast-track trials of known antivirals for prevention and cure of long COVID.
This should include more left-field therapies such as the diabetes drug metformin. This has possible dual benefits in the context of long COVID:
- its antiviral properties, which have demonstrated surprising efficacy against long COVID
- as a potential therapeutic in treating impairments related to fatigue.
However, another major thrust should be the development of new drugs and the establishment of clinical trial platforms for rapid testing.
Science has uncovered exciting therapeutic options. But translating these into forms usable in the clinic is a large hurdle that requires support and investment from governments.
Raising Awareness and Preventing Long COVID
The notion of “long infection” as a contributor or even the driver of long COVID is a powerful message. It could help demystify the condition in the eyes of the wider community and increase awareness among the general public as well as medical professionals.
It should help raise awareness in the community of the importance of reducing rates of re-infection. It is not just your first infection, but each subsequent COVID infection carries a risk of long COVID.
Long COVID is common and isn’t restricted to those at high risk of severe acute disease but affects all age groups. In one study, the highest impact was in those aged 30 to 49 years.
Preventive Measures and Future Outlook
So, for now, we all need to reduce our exposure to the virus with the tools available, a combination of:
- clean indoor air approaches. In its simplest form, this means being conscious of the importance of well-ventilated indoor spaces, opening the windows and improving airflow as COVID spreads through air. More sophisticated ways of ensuring indoor air is safe involve monitoring quality and filtering air in spaces that cannot be easily naturally ventilated
- using high-quality masks (that are well-fitting and don’t let air in easily, such as N95-type masks) in settings where you don’t have confidence of the quality of the indoor air and/or that are crowded
- testing, so you know when you’re positive. Then, if you’re eligible, you can get treatment. And you can be vigilant about protecting those around you with masks, staying at home where possible, and ventilating spaces
- staying up to date with COVID booster doses. Vaccines reduce long COVID and other post-COVID complications.
Hopefully one day there will be better treatments and even a cure for long COVID. But in the meantime, increased awareness of the biomedical basis of long COVID should prompt clinicians to take patients more seriously as they attempt to access the treatments and services that already exist.
Written by:
- Brendan Crabb, Director and CEO, Burnet Institute
- Gabriela Khoury, Theme Leader, Antiviral Immunity, Burnet Institute
- Michelle Scoullar, Senior Research Fellow, Burnet Institute
Adapted from an article originally published in The Conversation.
News
New Blood Test Detects Alzheimer’s and Tracks Its Progression With 92% Accuracy
The new test could help identify which patients are most likely to benefit from new Alzheimer’s drugs. A newly developed blood test for Alzheimer’s disease not only helps confirm the presence of the condition but also [...]
The CDC buried a measles forecast that stressed the need for vaccinations
This story was originally published on ProPublica, a nonprofit newsroom that investigates abuses of power. Sign up to receive our biggest stories as soon as they’re published. ProPublica — Leaders at the Centers for Disease Control and Prevention [...]
Light-Driven Plasmonic Microrobots for Nanoparticle Manipulation
A recent study published in Nature Communications presents a new microrobotic platform designed to improve the precision and versatility of nanoparticle manipulation using light. Led by Jin Qin and colleagues, the research addresses limitations in traditional [...]
Cancer’s “Master Switch” Blocked for Good in Landmark Study
Researchers discovered peptides that permanently block a key cancer protein once thought untreatable, using a new screening method to test their effectiveness inside cells. For the first time, scientists have identified promising drug candidates [...]
AI self-cloning claims: A new frontier or a looming threat?
Chinese scientists claim that some AI models can replicate themselves and protect against shutdown. Has artificial intelligence crossed the so-called red line? Chinese researchers have published two reports on arXiv claiming that some artificial [...]
New Drug Turns Human Blood Into Mosquito-Killing Weapon
Nitisinone, a drug for rare diseases, kills mosquitoes when present in human blood and may become a new tool to fight malaria, offering longer-lasting, environmentally safer effects than ivermectin. Controlling mosquito populations is a [...]
DNA Microscopy Creates 3D Maps of Life From the Inside Out
What if you could take a picture of every gene inside a living organism—not with light, but with DNA itself? Scientists at the University of Chicago have pioneered a revolutionary imaging technique called volumetric DNA microscopy. It builds [...]
Scientists Just Captured the Stunning Process That Shapes Chromosomes
Scientists at EMBL have captured how human chromosomes fold into their signature rod shape during cell division, using a groundbreaking method called LoopTrace. By observing overlapping DNA loops forming in high resolution, they revealed that large [...]
Bird Flu Virus Is Mutating Fast – Scientists Say Our Vaccines May Not Be Enough
H5N1 influenza is evolving rapidly, weakening the effectiveness of existing antibodies and increasing its potential threat to humans. Scientists at UNC Charlotte and MIT used high-performance computational modeling to analyze thousands of viral protein-antibody interactions, revealing [...]
Revolutionary Cancer Vaccine Targets All Solid Tumors
The method triggers immune responses that inhibit melanoma, triple-negative breast cancer, lung carcinoma, and ovarian cancer. Cancer treatment vaccines have been in development since 2010, when the first was approved for prostate cancer, followed [...]
Scientists Uncover Hidden Protein Driving Autoimmune Attacks
Scientists have uncovered a critical piece of the puzzle in autoimmune diseases: a protein that helps release immune response molecules. By studying an ultra-rare condition, researchers identified ArfGAP2 as a key player in immune [...]
Mediterranean neutrino observatory sets new limits on quantum gravity
Quantum gravity is the missing link between general relativity and quantum mechanics, the yet-to-be-discovered key to a unified theory capable of explaining both the infinitely large and the infinitely small. The solution to this [...]
Challenging Previous Beliefs: Japanese Scientists Discover Hidden Protector of Heart
A Japanese research team found that the oxidized form of glutathione (GSSG) may protect heart tissue by modifying a key protein, potentially offering a novel therapeutic approach for ischemic heart failure. A new study [...]
Millions May Have Long COVID – So Why Can’t They Get Diagnosed?
Millions of people in England may be living with Long Covid without even realizing it. A large-scale analysis found that nearly 10% suspect they might have the condition but remain uncertain, often due to [...]
Researchers Reveal What Happens to Your Brain When You Don’t Get Enough Sleep
What if poor sleep was doing more than just making you tired? Researchers have discovered that disrupted sleep in older adults interferes with the brain’s ability to clean out waste, leading to memory problems [...]
How to prevent chronic inflammation from zombie-like cells that accumulate with age
In humans and other multicellular organisms, cells multiply. This defining feature allows embryos to grow into adulthood, and enables the healing of the many bumps, bruises and scrapes along the way. Certain factors can [...]
