Infection prevention & vaccination
Infection Risks With IBD Therapies
Last Updated Nov 11, 2025
Inflammation, certain medicines, and combination treatment can raise infection risk in inflammatory bowel disease (IBD). Most serious infections are preventable. A simple checklist before starting immunosuppressive therapy, plus timely vaccines, lowers risk a lot. This article explains common infections seen with each therapy class and outlines the key screening steps used in the United States. (academic.oup.com)
Key takeaways
Systemic corticosteroids and combination therapy drive most infection risk in IBD. Use the lowest effective steroid dose and move to steroid‑sparing therapy when possible. (academic.oup.com)
Screen for tuberculosis, hepatitis B, varicella immunity, and HIV before advanced therapy. Treat latent TB and manage hepatitis B risk before starting immunosuppression. (academic.oup.com)
Class patterns: anti‑TNF drugs raise TB risk; JAK inhibitors raise shingles risk; S1P modulators need varicella immunity; vedolizumab has a favorable systemic safety profile. (academic.oup.com)
Vaccinate early: influenza, COVID‑19, pneumococcal, and recombinant zoster vaccine (RZV). Avoid live vaccines while immunosuppressed. (cdc.gov)
Consider Pneumocystis jirovecii pneumonia (PJP) prophylaxis with triple immunosuppression or calcineurin inhibitor combinations. (pmc.ncbi.nlm.nih.gov)
Before starting immunosuppressive therapy: the screening checklist
Tuberculosis: History, exam, chest X‑ray, and TST or IGRA. Test and treat latent TB before anti‑TNF or JAK therapy, ideally before any immunosuppression because steroids can blunt results. Re‑screen if risk changes. (academic.oup.com)
Hepatitis B: Order HBsAg, anti‑HBc, and anti‑HBs. Vaccinate if non‑immune. If HBsAg‑positive, start antiviral prophylaxis before biologics or small molecules. If anti‑HBc‑positive/HBsAg‑negative, monitor HBV DNA or HBsAg during therapy, and start antivirals if reactivation occurs. (journals.lww.com)
Hepatitis C and HIV: Baseline testing is commonly included in health maintenance and before immunosuppression. (journals.lww.com)
Varicella immunity: Confirm prior disease or vaccination. If non‑immune and time allows, give varicella vaccine before starting therapies that preclude live vaccines. RZV is recommended for immunocompromised adults aged 19 years and older to reduce shingles risk. (cdc.gov)
Strongyloides (targeted): In people who lived or traveled long‑term in endemic regions, screen or treat before prolonged steroids to prevent hyperinfection. (cdc.gov)
Baseline labs: CBC with differential and liver tests; repeat per drug labeling and clinical status. Some agents also require additional baseline testing.
How therapies affect infection risk
Class | Key infection risks | Screening and prevention notes |
|---|---|---|
Corticosteroids | Broad increase in serious infections and pneumonia; risk rises with higher dose and in older adults | Taper as soon as feasible. Vaccinate for influenza and pneumococcus. Consider PJP prophylaxis with prolonged high‑dose or when combined with other agents. (pubmed.ncbi.nlm.nih.gov) |
Thiopurines, methotrexate | Viral infections more frequent; risk amplifies with steroids or anti‑TNF | Check HBV serologies before use and vaccinate if needed. Minimize combination duration. (academic.oup.com) |
Anti‑TNF biologics | Reactivation or new TB; systemic bacterial, fungal infections | TB screening and treatment of latent TB before starting. Ensure HBV screening and vaccination. (academic.oup.com) |
Anti‑integrin (vedolizumab) | Favorable systemic profile; gastrointestinal infections a bit more common, especially in UC | Standard pre‑therapy screening; overall serious infection risk is lower than anti‑TNF in UC in several cohorts. (pubmed.ncbi.nlm.nih.gov) |
IL‑12/23 and IL‑23 inhibitors (ustekinumab, risankizumab, mirikizumab) | Generally low rates of serious or opportunistic infection; TB/HBV reactivation risk appears low | Screen for TB and HBV per standard practice; prophylaxis individualized. (academic.oup.com) |
JAK inhibitors (tofacitinib, upadacitinib) | Higher risk of shingles; serious bacterial, fungal, viral infections; TB reactivation | Give RZV when eligible. Test for latent TB before and during therapy; manage HBV risk. (pfizermedicalinformation.com) |
S1P modulators (ozanimod, etrasimod) | Lymphocyte sequestration increases infection risk; herpes zoster and rare cryptococcal meningitis reported | Confirm varicella immunity; consider zoster vaccination; obtain CBC before start; monitor for infections during and after therapy. (pfizermedical.com) |
Combination therapy | Risk increases stepwise with two or more immunosuppressants, highest with steroids plus thiopurine plus anti‑TNF | Prefer steroid‑sparing strategies and shortest possible overlap. (academic.oup.com) |
PJP: who needs prophylaxis
PJP is uncommon overall in IBD, but carries high morbidity when it occurs. ECCO suggests prophylaxis with trimethoprim‑sulfamethoxazole for triple immunosuppression or when a calcineurin inhibitor is involved. Many cases occur during corticosteroid exposure. Discuss prophylaxis if additional risk factors are present, such as lymphopenia or older age. (pmc.ncbi.nlm.nih.gov)
Vaccinate early
Give inactivated vaccines before or as soon as possible after starting therapy: seasonal influenza, COVID‑19, pneumococcal conjugate (PCV20 or PCV21, with universal recommendation beginning at age 50), hepatitis A and B, HPV, and Tdap per ACIP. (cdc.gov)
Give recombinant zoster vaccine to immunocompromised adults aged 19 and older and to all adults 50 and older. Live vaccines are generally avoided once immunosuppressed. (cdc.gov)
When to call the care team
Urgent evaluation is appropriate for fever above 101°F, new productive cough, shortness of breath, severe belly pain, uncontrolled diarrhea, new shingles‑like rash, or any infection that is not improving within 48 hours of starting antibiotics or antivirals. Therapy holds and restarts are individualized.
FAQs
Do all patients need TB treatment before biologics
No. Only those with active TB or latent TB need treatment. Everyone should be screened first with history, imaging, and TST or IGRA, ideally before any immunosuppression. (academic.oup.com)
How is hepatitis B handled if past exposure is found
If HBsAg is positive, start antiviral prophylaxis before immunosuppression. If HBsAg is negative but anti‑HBc is positive, monitor HBV DNA or HBsAg during treatment and treat if reactivation occurs. Vaccinate those who are non‑immune. (journals.lww.com)
Is vedolizumab safer for infections
Across multiple real‑world studies, vedolizumab shows a favorable systemic infection profile versus anti‑TNF in ulcerative colitis, though gastrointestinal infections may be more frequent. Choice still depends on disease and patient factors. (pubmed.ncbi.nlm.nih.gov)
Editor note: This article is educational and does not replace individualized medical advice.