Vedolizumab and Infection Risk in IBD: What a 2026 Meta-Analysis Found

Many people with inflammatory bowel disease ask the same question before starting vedolizumab: "Will this make me more vulnerable to infections?" It is a reasonable concern. Any treatment that affects immune activity in any way invites that kind of scrutiny, and IBD patients are often already dealing with a compromised quality of life that makes the idea of additional health complications feel especially heavy.

Vedolizumab (brand name Entyvio) has been in clinical use since 2014 as a treatment for adults with moderately to severely active Crohn's disease or ulcerative colitis. From the outset, its gut-selective mechanism was proposed as a reason it might carry a lower infection burden than some other biologics. A 2026 systematic review and meta-analysis set out to test that proposition with the largest pooled dataset to date.

How Vedolizumab Works

Vedolizumab is a monoclonal antibody that targets a protein called integrin alpha-4 beta-7, found on the surface of certain T-lymphocytes. By blocking this integrin, the drug prevents those immune cells from crossing from the bloodstream into the lining of the gut, where they would otherwise drive the inflammation that underlies IBD.

What makes this mechanism distinctive is its selectivity. While some biologic therapies for IBD reduce immune activity broadly across the body, vedolizumab acts primarily at the gut. This gut-selective profile was always expected to translate into a lower systemic infection burden compared with treatments that suppress the immune system more widely. Whether the real-world and trial data bear that out across a large patient population was exactly what the 2026 meta-analysis aimed to establish.

What the Meta-Analysis Found

The systematic review and meta-analysis, published in Frontiers in Medicine in June 2026 (Zhang L, Hao X, Cui Y, et al.), included 66 studies and data from approximately 24,000 patients with IBD who had been treated with vedolizumab (Zhang L et al., Frontiers in Medicine, 2026). Infection outcomes were standardised using the Common Terminology Criteria for Adverse Events (CTCAE v5.0), and the analysis used random-effects models with appropriate adjustments to account for the variation across studies.

The overall pooled infection incidence was 13.08% (95% CI: 9.85 to 17.18%). The most common type of infection was respiratory tract infections, which accounted for approximately 4.25% of patients. Serious systemic or rare infections were infrequent.

When the researchers compared vedolizumab's infection risk with that of other therapies, the results showed:

• Versus TNF inhibitors (such as infliximab or adalimumab): No significant difference (risk ratio 0.91)
• Versus placebo: No significant difference (risk ratio 1.02)
• Versus ustekinumab (Stelara): Vedolizumab was associated with a modestly higher infection risk (risk ratio 1.63)

The authors concluded that vedolizumab carries a moderate infection risk, driven primarily by mild respiratory events, with a safety profile broadly comparable to TNF inhibitors and placebo. The comparison with ustekinumab showing a somewhat higher risk is a meaningful finding for shared decision-making between patients and their doctors. The researchers also noted that substantial heterogeneity across the 66 included studies, driven by differences in study design and geographic region, limits the clinical utility of the pooled incidence figure in isolation. The comparative analysis, putting vedolizumab side by side with specific alternative therapies, is the more actionable part of the evidence.

What This Means for Patients

The findings offer meaningful context. The available evidence does not suggest that vedolizumab significantly increases infection risk compared with the most commonly used alternative biologics, or compared with placebo. The infection burden that does occur is dominated by respiratory infections, which are common in the general population and are usually mild.

At the same time, the presence of any biologic treatment in an IBD regimen warrants ongoing vigilance. People on vedolizumab should discuss infection-related precautions with their care team, including staying current with vaccinations. Certain live vaccines are not recommended during treatment, and annual influenza vaccination is generally advised. Knowing when to seek care promptly, particularly if a fever or sign of infection develops, is part of managing any advanced IBD therapy safely.

It is also worth noting that this meta-analysis found meaningful variation across the studies it included. Infection rates are not uniform across all IBD populations, and individual risk depends on factors including underlying disease severity, concurrent medications, and general health.