Learn what current research says about monoclonal antibodies for Long COVID, including antiviral treatments such as Pemgarda, Sipavibart and Evusheld, the theory of viral persistence, and whether these medicines may help selected groups of patients.

There is currently no monoclonal antibody approved to treat Long COVID. Researchers are investigating whether antiviral monoclonal antibodies could benefit a small subgroup of patients, particularly those with evidence of viral persistence or specific immune abnormalities. While early laboratory research, case reports and small clinical studies have shown encouraging signals, larger clinical trials have not yet demonstrated consistent benefits across the wider Long COVID population. At present, monoclonal antibodies remain experimental and should only be used within specialist care or approved clinical research.

Last evidence review: July 2026.

Key Findings

• There is currently no monoclonal antibody approved to treat Long COVID.
• Researchers are actively investigating whether some monoclonal antibodies could help selected patients, particularly those with evidence of viral persistence or immune dysfunction. While early studies and case reports have shown encouraging results in some individuals, larger clinical trials have not yet demonstrated consistent benefits across the wider Long COVID population.
• At present, monoclonal antibodies remain experimental for Long COVID and should only be used within specialist care or clinical research.

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What Are Monoclonal Antibodies?

If you’ve been reading about Long COVID research, you’ve probably come across names such as Evusheld, Sipavibartor Pemgarda.They’re all monoclonal antibodies but what does that actually mean?

Monoclonal antibodies are laboratory-produced proteins designed to recognise one very specific target. Some attach to viruses, helping prevent them from infecting cells. Others block particular immune pathways involved in inflammation or autoimmune disease.Unlike many traditional medicines, monoclonal antibodies are highly targeted. Instead of affecting the whole immune system, they are designed to interact with one specific molecule, receptor or biological process.That precision is one of the reasons they have transformed the treatment of many diseases, including certain cancers, autoimmune conditions and severe inflammatory illnesses.

Naturally, researchers have begun asking whether the same approach could help people living with Long COVID.

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Why Are Researchers Interested in Monoclonal Antibodies?

One of the biggest discoveries since the pandemic is that Long COVID appears to involve several different biological mechanisms rather than a single cause. Research has identified evidence of immune dysregulation, viral persistence, endothelial dysfunction and autoimmune features in different groups of patients. Importantly, not everyone shows the same pattern. This may explain why one treatment can produce dramatic improvements in one person while having little effect in another. Monoclonal antibodies are attractive because they target specific biological pathways rather than suppressing the immune system as a whole.If researchers can identify which mechanism is driving symptoms in an individual patient, a targeted therapy may eventually prove more effective than a one-size-fits-all approach.

That idea often called precision medicine is becoming one of the biggest goals in Long COVID research.

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Why Aren’t Monoclonal Antibodies Already Used for Long COVID?

This is one of the most common questions patients ask. After all, many people have read stories online describing significant improvements after receiving monoclonal antibodies. Some of those stories are genuine.The problem is that individual experiences cannot tell us whether the treatment caused the improvement, whether recovery would have happened anyway, or whether only a very specific group of patients is likely to benefit.That’s why researchers rely on carefully designed clinical trials.

So far, those studies have produced mixed results. While some patients appear to improve, others experience little or no benefit. At present, there is not enough evidence to recommend monoclonal antibodies as a routine treatment for Long COVID. That doesn’t mean the idea is wrong.It simply means researchers are still trying to answer the most important question:

Who, if anyone, is most likely to benefit?

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Monoclonal Antibodies: Could They Help Long COVID?

Most monoclonal antibodies currently discussed in Long COVID research were not originally developed for Long COVID. They were created during the COVID-19 pandemic to prevent or treat acute COVID-19 infection, particularly in people at high risk of severe illness or those whose immune systems could not produce an adequate response to vaccination.This included people receiving chemotherapy, organ transplant recipients, individuals with immune deficiencies and others taking medications that significantly suppressed the immune system.

These medicines were designed to recognise the SARS-CoV-2 virus itself, preventing it from entering healthy cells and helping reduce the risk of severe infection. As researchers learned more about Long COVID, an important question emerged.

If viral material remains in the body after the initial infection, could these same medicines also help some people with Long COVID? That question is now being actively investigated.

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Why Does Viral Persistence Matter?

One of the leading theories in Long COVID is that small amounts of viral material may remain in the body long after the initial infection has resolved. This is known as viral persistence. It does not necessarily mean the virus is actively replicating in the same way it does during acute COVID-19.Instead, researchers believe viral proteins or small viral reservoirs may continue stimulating the immune system in some people, potentially contributing to ongoing inflammation and persistent symptoms.If this theory proves correct, antiviral monoclonal antibodies could potentially benefit a carefully selected subgroup of patients.The challenge is that we currently have no reliable clinical test to identify who has viral persistence and who does not. It’s also possible that any benefit from these therapies, if confirmed, could involve mechanisms beyond simply eliminating persistent viral material, although this remains speculative and is still being investigated.

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Which Monoclonal Antibodies Are Being Studied?

Several monoclonal antibodies have attracted attention during the pandemic, although their roles have changed as the virus has evolved.

Evusheld (tixagevimab + cilgavimab)

Evusheld was one of the first long-acting monoclonal antibody combinations developed to prevent COVID-19 infectionin people who were unlikely to respond adequately to vaccination. It was not developed to treat Long COVID. As new SARS-CoV-2 variants emerged, however, Evusheld became much less effective because the virus changed the part of the spike protein the antibodies were designed to recognise.Today, Evusheld is no longer widely used because newer variants can largely escape its protective effect.

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Pemgarda (pemivibart)

Pemgarda is a newer monoclonal antibody authorised in some countries to provide pre-exposure protection against COVID-19 for certain moderately or severely immunocompromised individuals.Like Evusheld, it was developed to prevent infection, not to treat Long COVID. Researchers are interested in whether medicines like Pemgarda could eventually help patients if viral persistence proves to be an important driver of Long COVID.At present, however, there is no evidence that Pemgarda is an approved treatment for Long COVID, and its use remains limited to its licensed indications.

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Sipavibart

Sipavibart is another long-acting monoclonal antibody developed to protect vulnerable individuals against COVID-19.Because it has been designed to recognise newer SARS-CoV-2 variants, it has generated considerable interest following the reduced effectiveness of earlier antibodies such as Evusheld.As with Pemgarda, Sipavibart is not approved as a treatment for Long COVID. Researchers are watching closely to see whether newer antiviral monoclonal antibodies might eventually have a role in carefully selected patients, particularly if future studies confirm that viral persistence contributes to Long COVID in some individuals.

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Why Did Some COVID Monoclonal Antibodies Stop Working?

One of the biggest challenges with antiviral monoclonal antibodies is that the virus changes over time.These medicines recognise very specific parts of the SARS-CoV-2 spike protein. As new variants emerge, those target sites can change, making older monoclonal antibodies less effective or, in some cases, ineffective altogether.This is why several monoclonal antibodies that were highly effective early in the pandemic are no longer routinely used today.Rather than proving that monoclonal antibodies don’t work, it highlights an important challenge: they need to keep evolving alongside the virus itself.

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What Does the Current Evidence Show?

Early case reports describing improvements after antiviral monoclonal antibody treatment generated considerable interest within the Long COVID community. However, larger clinical studies have produced more mixed results. Some patients appear to improve, while many experience little or no measurable benefit. This does not necessarily disprove the viral persistence theory.Instead, it suggests that antiviral monoclonal antibodies are unlikely to benefit everyone with Long COVID and may only help a subgroup of patients whose illness is driven by persistent viral reservoirs.Identifying that subgroup remains one of the biggest challenges in current Long COVID research. Researchers’ continued interest is not based on patient stories alone. Laboratory studies have identified persistent viral proteins, immune abnormalities and other biological findings in some people with Long COVID that provide a scientific rationale for investigating targeted therapies. Whether antiviral monoclonal antibodies can modify these processes in clinical practice remains uncertain, but the underlying biological questions are considered important enough to justify ongoing trials.

Can You Get Monoclonal Antibodies for Long COVID?

At present, no monoclonal antibody is approved specifically to treat Long COVID in the UK, the United States or most other countries. While several monoclonal antibodies have been authorised to prevent or treat acute COVID-19 in selected patients, this is very different from using them to treat persistent symptoms months or years after infection. Outside of clinical trials, monoclonal antibodies are not routinely prescribed for Long COVID. If they are used, it is usually because the patient has another recognised medical condition for which the treatment is already approved, rather than Long COVID itself.

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Are Monoclonal Antibodies Available on the NHS?

For most people with Long COVID, the answer is no. The NHS currently uses monoclonal antibodies only for specific licensed indications, such as preventing COVID-19 in certain severely immunocompromised patients or treating other established diseases like some cancers and autoimmune conditions. Long COVID is not currently an approved indication, meaning these medicines are not routinely available through NHS Long COVID services. This may change if future clinical trials demonstrate clear benefits in carefully selected groups of patients.

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Can You Buy Monoclonal Antibodies Privately?

This is another common question. In theory, some monoclonal antibodies can be accessed through private healthcare, but this does not mean they can be prescribed for Long COVID. Doctors must prescribe medicines responsibly and according to the available evidence. Because monoclonal antibodies remain experimental for Long COVID, many specialists would not recommend private treatment outside a properly designed clinical trial. Even if private access were possible, treatment decisions should always be based on medical assessment rather than anecdotal reports or stories shared online.

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How Much Do Monoclonal Antibodies Cost?

Monoclonal antibodies are among the most expensive medicines in modern healthcare. Unlike conventional tablets, they are complex biological medicines produced using living cells under highly controlled laboratory conditions. Manufacturing is time-consuming, requires specialised facilities and involves strict storage and transport requirements. Depending on the specific medicine and country, treatment can cost hundreds to several thousand pounds or dollars per dose, with some therapies costing significantly more.This is one reason why researchers need strong evidence before these medicines can become widely available for new conditions such as Long COVID.

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Who Might Benefit in the Future?

One of the biggest misconceptions is that monoclonal antibodies are either a cure or don’t work at all. The reality is probably much more complicated. Researchers increasingly believe that only a subgroup of people with Long COVID may benefit from antiviral monoclonal antibodies. These could include patients with evidence suggesting persistent viral reservoirs or particular immune abnormalities, although no reliable biomarkers currently exist to identify these groups in routine clinical practice. This is why current research is focusing on precision medicine matching treatments to the biology of each individual rather than assuming everyone with Long COVID has the same underlying illness.

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What Needs to Happen Next?

The next few years are likely to answer some of the biggest questions surrounding monoclonal antibodies and Long COVID. Researchers need to determine:

• Does viral persistence occur in all patients or only some?
• Which biological markers predict a response to treatment?
• Which monoclonal antibodies remain effective against newer variants?
• When is the best time to give treatment?
• Can combining antiviral therapies with other treatments improve outcomes?

Finding these answers may prove just as important as developing entirely new medicines. Rather than searching for one treatment that works for everyone, researchers are increasingly trying to identify the right treatment for the right patient.

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Want to Learn More About Immunotherapy?

Monoclonal antibodies are just one type of immune-targeted treatment being explored for Long COVID. Researchers are also investigating therapies such as IVIG, rituximab and other approaches that aim to regulate the immune system rather than target the virus directly.Our complete guide explains how these treatments differ, what the current evidence shows, and why personalised medicine is becoming one of the most promising areas of Long COVID research.

→ Immunotherapy for Long COVID: IVIG, Rituximab and Monoclonal Antibodies

The Bottom Line

Monoclonal antibodies remain one of the most promising but also one of the most misunderstood areas of Long COVID research. They were originally developed to prevent or treat acute COVID-19, particularly in people who could not rely on vaccination alone. They were not designed to treat Long COVID, and no monoclonal antibody is currently approved for that purpose. Even so, ongoing research continues to explore whether selected patients particularly those with evidence of viral persistence or specific immune abnormalities could eventually benefit from targeted monoclonal antibody therapies. For now, the evidence supports cautious optimism rather than certainty. The science is moving quickly, but the most important breakthrough may not be discovering a completely new medicine. It may be learning which patients are most likely to benefit from the medicines we already have.

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Frequently Asked Questions

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Explore Related Topics

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Disclaimer

This article is intended for educational and informational purposes only and should not be considered medical advice.Research into Long COVID is evolving rapidly, and many potential treatments including monoclonal antibodies remain experimental. The information presented here reflects the current scientific evidence at the time of writing but may change as new research becomes available.

Treatment decisions should always be made in consultation with a qualified healthcare professional who canassess your individual medical history, symptoms and potential risks. Never start, stop or change any medication based solely on information found online.

References

Putrino D, Nath A, Peluso MJ, et al. Advances in understanding the pathophysiology of Long COVID. Nature Medicine. 2025.

World Health Organization (WHO). Clinical case definition of post COVID-19 condition by a Delphi consensus.2021.

National Institute for Health and Care Excellence (NICE). COVID-19 rapid guideline: Managing the long-term effects of COVID-19 (NG188).

Davis HE, McCorkell L, Vogel JM, Topol EJ. Long COVID: major findings, mechanisms and recommendations. Nature Reviews Microbiology. 2023.

Proal AD, VanElzakker MB. Long COVID or Post-acute Sequelae of COVID-19 (PASC): An Overview of Biological Factors. Frontiers in Microbiology. 2021.

Peluso MJ, Deeks SG. Mechanisms of Long COVID. Nature Reviews Immunology. 2024.

National Academies of Sciences, Engineering, and Medicine. Toward a Common Research Agenda in Long COVID. 2024.

RECOVER Initiative. Researching the long-term effects of COVID-19. (NIH)

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