Humira and COVID-19: Infection Risk, Vaccines, and Timing

People taking Humira (adalimumab) do not appear to face a higher risk of catching COVID-19 or developing severe illness from it, according to multiple large registries and observational studies conducted during the pandemic. The evidence actually leans in the opposite direction: TNF inhibitors like Humira were consistently associated with outcomes as good as or better than many other immunosuppressive therapies. That finding surprised many patients and doctors early in the pandemic, when the instinct was to assume that any drug suppressing the immune system would leave people more vulnerable.

Why TNF Blockers Were Expected to Be a Problem

Humira works by blocking tumor necrosis factor-alpha (TNF-α), one of the immune system’s key inflammatory signaling molecules. Because TNF-α helps coordinate the body’s defense against infections, the reasonable assumption in early 2020 was that patients on Humira would have a harder time fighting off SARS-CoV-2. That concern drove some patients to stop their medication without consulting their doctors, and it prompted researchers to closely track COVID-19 outcomes in people on biologics.

What emerged was more nuanced. TNF-α turns out to be a double-edged molecule in COVID-19. It is one of the earliest inflammatory signals the body produces when infected with SARS-CoV-2, and it helps recruit immune cells to fight the virus. But it also plays a central role in the runaway inflammation that makes severe COVID dangerous. TNF-α-driven inflammation can damage lung tissue, promote fibrosis, and contribute to the fluid buildup that leads to acute respiratory distress syndrome.¹ TNF-α also activates the NF-κB pathway, which amplifies the production of additional inflammatory molecules, creating a feedback loop that can spiral into the cytokine storm associated with severe and fatal COVID cases.²

So blocking TNF-α with Humira takes away some early immune defense, but it also removes one of the main drivers of the inflammatory damage that makes COVID-19 deadly. This trade-off helps explain why the net effect on patients seems to be neutral or even slightly favorable.

What the Infection Data Show

Several studies looked at whether people on TNF inhibitors caught COVID-19 at higher rates than other patients. They did not. A review of immunosuppressed patients with inflammatory bowel disease found that those receiving biologics, including TNF blockers, did not have an increased risk of contracting SARS-CoV-2 or developing more severe disease.³ A population-based study of psoriasis patients found that TNF inhibitor use was associated with a comparable rate of COVID-19 infection when compared to other standard treatments like methotrexate or acitretin.⁴

One case-control study went further, reporting that adalimumab use was associated with a substantially lower risk of developing COVID-19 in patients with rheumatoid arthritis or spondyloarthropathy, with the odds of infection reduced by as much as 97% compared to non-users.⁵ That figure is striking, though it comes from a single study and should be interpreted cautiously. An earlier review noted that at the time, it was impossible to draw firm conclusions about differences in COVID-19 risk between various immunomodulatory therapies.⁶ Still, the consistent theme across the literature is that TNF inhibitors do not raise infection risk, and some data suggest they may lower it.

Severity, Hospitalization, and Death

For patients who did contract COVID-19 while on Humira, the outcomes were reassuring. A large UK study published in The Lancet Rheumatology examined COVID-19-related hospital admissions, critical care admissions, and deaths among people with immune-mediated inflammatory diseases. Compared to those on standard systemic therapy, individuals on TNF inhibitors showed no increased risk of COVID-19-related death, critical care admission, or hospitalization.⁷

The psoriasis cohort study found a particularly encouraging signal: TNF inhibitor use was linked to a lower risk of COVID-19-related hospitalization compared to methotrexate, a commonly used alternative therapy.⁸ Data from the SECURE-IBD registry, an international database tracking COVID-19 outcomes in IBD patients, showed that TNF antagonist monotherapy served as the reference point against which other drug classes were measured, and it compared favorably. Thiopurine monotherapy and combination therapy with a TNF antagonist plus a thiopurine were each associated with roughly four times the odds of severe COVID-19 compared to TNF antagonist monotherapy alone.⁹

A study from Andalusia examining hospitalization and mortality found no association between different rheumatic disease drugs and worse outcomes, but noted that larger registry data had pointed toward TNF blockers being associated with a lower likelihood of hospitalization compared to other treatments.¹⁰ A broader review of the evidence likewise noted that most studies found no association between biologics and severe COVID-19, and some even hinted at reduced hospitalization risk with TNF inhibitors, though residual confounding remains a possibility.¹¹

How Humira Compares to Other Biologics

Not all biologics fared equally during the pandemic, and this distinction matters for patients and clinicians weighing treatment options. Data from the COVID-19 Global Rheumatology Alliance registry, which tracked nearly 2,900 people with rheumatoid arthritis on biologic or targeted synthetic therapies, found that TNF inhibitors were the safest group. Rituximab, a drug that depletes B cells, was associated with more than four times the odds of worse COVID-19 severity compared to TNF inhibitors. JAK inhibitors were associated with about twice the odds of worse outcomes.¹²

The UK Lancet study echoed this pattern. Rituximab users had a substantially higher hazard of COVID-19-related death and critical care admission compared to those on standard systemic therapy. JAK inhibitors were associated with higher hospitalization risk. Meanwhile, TNF inhibitors, IL-12/IL-23 inhibitors, IL-17 inhibitors, and IL-6 inhibitors showed no increased risk on any of those measures.¹³ This hierarchy became clinically relevant: some rheumatologists delayed rituximab infusions or timed them around vaccination windows, while patients on TNF inhibitors like Humira were generally advised to continue their treatment without interruption.

COVID-19 Vaccines and Humira

A major concern for Humira patients was whether the drug would blunt their response to COVID-19 vaccines. The short answer is that Humira modestly reduces antibody levels but does not prevent a meaningful immune response. A study of patients with axial spondyloarthritis receiving either adalimumab or secukinumab found robust seroconversion in all participants after vaccination with the Pfizer-BioNTech mRNA vaccine. The overall antibody and T-cell responses did not differ significantly between patients on these biologics and healthy individuals.¹⁴

The cellular side of the immune response appeared particularly well preserved. A study tracking IBD patients on various immune-modifying therapies found that spike-specific T-cell responses were not only induced at levels comparable to healthy controls but were sustained at higher levels for up to six months after vaccination, especially in those on TNF inhibitor therapy.¹⁵ This is an important finding because T cells provide a longer-lasting and broader layer of protection than antibodies alone, targeting infected cells directly and responding to viral variants that might partially escape antibody recognition.

Antibody titers do appear somewhat affected over time. A study comparing patients on original adalimumab versus a biosimilar version found that antibody levels held relatively stable in the weeks after the second vaccine dose in patients on the original product, while those on the biosimilar saw a significant decline.¹⁶ That discrepancy was unexpected and not fully explained, though differences in the formulation or patient characteristics could play a role. The practical takeaway is that while antibody levels can wane somewhat on Humira, the cellular immune response appears intact, and most patients mount a clinically meaningful response to vaccination.

Drug Levels and Antibody Formation After Natural Infection

An interesting wrinkle emerged from therapeutic drug monitoring data. A large study of over 11,000 patients on biologic treatments found that adalimumab and infliximab impaired the body’s ability to generate SARS-CoV-2 antibodies after natural infection. Among adalimumab-treated patients, those with undetectable drug levels in their blood were more likely to test positive for SARS-CoV-2 antibodies than those with detectable drug levels, suggesting that higher adalimumab concentrations may suppress the antibody response to the virus itself.¹⁷

This does not mean the drug left people unprotected. Antibody seropositivity is only one marker of immunity; as noted in the vaccine studies, T-cell responses on adalimumab remain robust. But it does mean that antibody-based tests for prior COVID-19 infection may undercount cases in Humira patients. If you are on adalimumab and take a blood test to check whether you have had COVID, a negative antibody result does not necessarily mean you were never infected.

Was Adalimumab Tried as a COVID-19 Treatment?

Given the role of TNF-α in driving severe COVID-19 inflammation, researchers tested whether giving adalimumab to hospitalized patients could improve outcomes. The results were mixed. A randomized controlled trial evaluating adalimumab in combination with remdesivir and dexamethasone for severe COVID-19 found that the addition of adalimumab did not improve outcomes beyond the standard treatment regimen.¹⁸

A separate trial looking at adalimumab plus pulsed corticosteroids in patients with acute respiratory distress syndrome from COVID-19 reported more promising findings: patients in the adalimumab group had significantly shorter hospital stays and improved neurological scores.¹⁹ These conflicting results, combined with the small size of both trials, mean adalimumab has not been adopted as a COVID-19 treatment. Other anti-inflammatory approaches, particularly corticosteroids and IL-6 inhibitors like tocilizumab, had stronger evidence and wider uptake.

Combination Therapy and When the Risk Picture Changes

While Humira alone showed favorable COVID-19 outcomes, combining it with certain other immunosuppressants changed the equation. The SECURE-IBD registry data made this clear: patients on TNF antagonist monotherapy had much lower odds of severe COVID-19 than those on a TNF antagonist combined with a thiopurine like azathioprine or mercaptopurine.²⁰ A smaller study found that COVID-19 infections clustered among patients on combination biologic-plus-immunomodulator therapy, while no cases occurred in those on certain single-agent biologics.²¹

Glucocorticoid use also matters. Multiple registries identified daily prednisone doses of 10 mg or above as a risk factor for worse COVID-19 outcomes, independent of which biologic a patient was on. For patients taking Humira alongside oral steroids, the steroid component likely contributes more to COVID-19 vulnerability than the biologic itself. This distinction became relevant for treatment decisions: where possible, clinicians tried to minimize corticosteroid exposure during COVID surges, while maintaining biologic therapy.

Patients Who Stopped Humira Out of Fear

Early pandemic anxiety led some patients to discontinue Humira on their own. A German cross-sectional study tracked this phenomenon, noting that Google searches for Humira correlated with the number of patients reporting that they had stopped their immunomodulatory medication.²² Stopping Humira abruptly carries its own risks: disease flares, potential formation of anti-drug antibodies that can reduce the medication’s effectiveness if restarted, and the general health consequences of uncontrolled inflammation.

With the accumulating evidence that TNF inhibitors do not worsen COVID-19, every major rheumatology and gastroenterology society eventually issued guidance recommending that patients continue their biologic therapy during the pandemic. The consensus has held: the risk of stopping Humira and flaring your underlying disease outweighs the risk that the drug poses for COVID-19.

Children on Humira and COVID-19 Vaccination

Pediatric data are thinner, but a prospective multicenter study of children aged 4 to 11 with autoimmune inflammatory rheumatic diseases found reassuring results. Adverse event rates after COVID-19 vaccination were similar between children with autoimmune conditions and healthy controls. Breakthrough COVID-19 infection rates were also comparable, and all infections in the autoimmune disease group were symptomatic but mild, with no severe cases reported.²³ The study population included children on various biologics and disease-modifying therapies, and disease activity remained stable and low after vaccination. For parents of children on Humira, this supports both the safety of COVID-19 vaccination and the reassurance that the medication does not put kids at special risk.

Rare Complications Worth Knowing About

While the general picture is favorable, case reports have documented unusual immune reactions in Humira patients who contract COVID-19. One published case described a 45-year-old man with spondyloarthropathy managed on adalimumab who developed a widespread pustular rash resembling generalized pustular psoriasis after a COVID-19 infection. The infection appeared to trigger an aberrant immune response that, in the context of TNF blockade, manifested as an aggressive skin eruption. Such cases are rare, but they illustrate that the interplay between SARS-CoV-2 and immune-modifying drugs can occasionally produce unexpected clinical scenarios. They do not change the overall risk-benefit calculation for continuing Humira, but they are worth flagging for patients and doctors to recognize.

Timing Your Injection Around Vaccination or Infection

A practical question many Humira patients have asked is whether they should time their injections differently around COVID-19 vaccination. Formal guidance on this has varied by specialty society and evolved over time. The American College of Rheumatology initially suggested holding adalimumab for a brief period after each vaccine dose to optimize the immune response, though this recommendation was not adopted universally and was based on expert opinion rather than strong evidence specific to adalimumab. Given that the studies cited above show intact T-cell responses and adequate seroconversion in adalimumab-treated patients, many clinicians have taken a pragmatic approach: if timing the injection to fall a few days after a vaccine dose is convenient, do it, but do not skip or significantly delay your Humira dose to accommodate vaccination.

During an active COVID-19 infection, the decision is more complex and should involve your prescribing doctor. Some clinicians recommend holding the injection during the acute phase of illness, since TNF blockade could theoretically slow the initial viral clearance. Others argue that continuing it may help prevent the inflammatory spiral that makes COVID dangerous. There is no randomized trial specifically addressing this question for adalimumab, so the answer tends to come down to the severity of the infection, the patient’s underlying disease activity, and individual clinical judgment.