Infection Prevention & Vaccinations

Vaccination and infection prevention are central to safe treatment for Crohn’s disease and ulcerative colitis, especially when immune‑suppressing medicines are used. These drugs help control inflammation but also raise the risk of serious infections, many of which are preventable. This article outlines which infections are usually screened for, which vaccines are recommended, and how timing and vaccine type change once immunosuppressants are part of the treatment plan.

Key takeaways

• Immune‑suppressing IBD medicines increase infection risk, so screening for infections and keeping vaccines up to date is essential.

• Inactivated (non‑live) vaccines are safe on immunosuppressants; live vaccines are usually avoided once immune suppression has started.

• Before strong immunosuppressants, most patients are screened for tuberculosis (TB), hepatitis B, and sometimes hepatitis C, HIV, and past chickenpox.

• Adults with IBD on immunosuppressants should receive flu, COVID‑19, pneumococcal, shingles, hepatitis B, Tdap, and other age‑ and risk‑based vaccines.

• Large studies show that recommended vaccines are generally safe in IBD and do not meaningfully increase flare risk.(pubmed.ncbi.nlm.nih.gov)

Why infection prevention matters in IBD treatments

IBD itself can slightly increase infection risk, and this risk becomes higher with many modern treatments that weaken parts of the immune system.(academic.oup.com)
At the same time, vaccination rates in IBD remain lower than in the general population, especially for flu, pneumococcal, and hepatitis B vaccines.(pubmed.ncbi.nlm.nih.gov)

Guidelines from ACG, AGA, and ECCO now treat infection prevention as a core part of IBD care, not an optional add‑on.(pubmed.ncbi.nlm.nih.gov)
They recommend reviewing vaccine status at diagnosis and regularly during follow‑up, especially before starting or changing immunosuppressive therapy.(mdcalc.com)

Who counts as “immunosuppressed” in IBD?

For vaccine and infection‑risk decisions, a patient is usually considered immunosuppressed if taking:(pubmed.ncbi.nlm.nih.gov)

• Systemic corticosteroids at moderate or high doses for more than about 2 weeks.

• Thiopurines (azathioprine, 6‑mercaptopurine) or methotrexate.

• Biologic agents, such as anti‑TNF drugs, anti‑integrin therapy, and IL‑12/23 or IL‑23 inhibitors.

• Small‑molecule medicines, such as JAK inhibitors or S1P receptor modulators.

• Combination therapy, for example a biologic plus a thiopurine.

Rectal therapies, 5‑ASA drugs, and budesonide alone usually do not cause the same level of systemic immune suppression, though they may still be used alongside stronger agents.(pubmed.ncbi.nlm.nih.gov)

Infection screening before immunosuppressive therapy

Core screening tests

Before starting a biologic, JAK inhibitor, S1P modulator, or long‑term high‑dose steroids, most guidelines recommend:(academic.oup.com)

• Tuberculosis (TB)

• Blood test (IGRA) or skin test.

• Chest X‑ray if there is a positive test or strong clinical suspicion.

• Latent TB is usually treated before or alongside starting therapy.

• Hepatitis B virus (HBV)

• Blood tests for HBsAg, anti‑HBs, and anti‑HBc.

• If chronic infection is present, antiviral treatment and hepatology input are needed before immune‑suppressing drugs.

• Hepatitis C and HIV

• Often recommended at baseline, especially if other risk factors are present, because undiagnosed infection may worsen on therapy and changes treatment choices.

• Varicella‑zoster virus (VZV)

• History of chickenpox or 2‑dose varicella vaccine.

• A blood test for varicella immunity if history is uncertain.

Clinicians may also consider local infection risks, travel plans, and childhood vaccine records when deciding what to screen and vaccinate for.(academic.oup.com)

What happens with positive results?

If latent TB or chronic hepatitis B is found, treatment plans usually combine:

• Antimicrobial therapy (for TB or HBV).

• Careful timing of when to start or adjust immunosuppressants.

• Coordination with infectious disease or liver specialists.(pubmed.ncbi.nlm.nih.gov)

The goal is to control IBD while lowering the chance of infection reactivation.

Vaccine principles for people on immunosuppressants

Timing: earlier is better, but do not delay urgent therapy

Best‑practice guidance recommends updating vaccines as early as possible, ideally at diagnosis or before a major treatment change.(pubmed.ncbi.nlm.nih.gov)
However, guidelines also state that urgently needed immunosuppressive therapy should not be excessively delayed just to complete vaccines; inactivated vaccines can be given after therapy has started.(gastro.org)

Live vs inactivated vaccines

The key safety rule is about vaccine type:

Guidelines from ACG and CDC state that adults with IBD on immune‑modifying therapy should not receive live vaccines.(guidelinecentral.com)

Safety and flare risk

Systematic reviews and meta‑analyses show that recommended inactivated vaccines in IBD have mostly mild local or short‑lived systemic side effects. They have very low rates of IBD flare, similar to background flare rates.(pubmed.ncbi.nlm.nih.gov)
COVID‑19 vaccines appear effective in preventing infection and do not increase flare risk overall.(pubmed.ncbi.nlm.nih.gov)

Core adult vaccine checklist for immunosuppressed IBD (U.S.)

Specific products and schedules follow the CDC adult immunization schedule and may change over time.(cdc.gov)
Common recommendations for adults with IBD on immunosuppressants include:(mdcalc.com)

• Influenza (flu shot)

• Yearly inactivated flu shot for all adults.

• Nasal spray flu vaccine (live) is not used in immunosuppressed patients.

• COVID‑19

• Vaccination and boosters as advised for people with immunocompromising conditions.

• Many patients need additional or higher‑risk‑group doses.

• Pneumococcal (PCV20 or PCV21 ± PPSV23)

• Recommended for adults on immune‑modifying therapy and for older adults, even under age 65.

• Exact timing depends on age and any previous pneumococcal vaccines.

• Recombinant zoster vaccine (RZV, Shingrix)

• Two‑dose, non‑live shingles vaccine.

• Recommended for all adults with IBD aged 50 and older, and for adults 19 and older on immunosuppressive therapy.(guidelinecentral.com)

• Hepatitis B

• Full vaccine series for anyone without documented immunity or chronic infection.

• IBD patients respond well overall, though some may need higher‑dose or two‑dose (Heplisav‑B) schedules.(pubmed.ncbi.nlm.nih.gov)

• Tdap / Td

• One‑time Tdap in adulthood, then Td or Tdap booster every 10 years.

• Human papillomavirus (HPV)

• Routine through age 26 if not fully vaccinated.

• Possible up to age 45 using shared decision making.

• Hepatitis A, meningococcal, RSV, mpox and others

• Given based on age, liver disease, asplenia, sexual exposures, outbreaks, travel, and other risk factors.(cdc.gov)

• MMR and varicella (live vaccines)

• For adults who lack immunity and are not yet immunosuppressed.

• Usually given at least 4 weeks before starting strong immunosuppressants and avoided afterward.(gastro.org)

Non‑vaccine infection‑prevention strategies

Vaccines work best as part of a broader plan:

• Prompt medical review for high fevers, new cough, severe sore throat, or painful blisters.

• Good hand hygiene and avoiding close contact with people who have known contagious infections when possible.

• Safe food and water practices, especially when traveling.

• Careful planning for travel vaccines and malaria prophylaxis before trips to higher‑risk regions.(academic.oup.com)

Household members are encouraged to stay up to date on their own vaccines, including flu and COVID‑19, to create an extra “cocoon” of protection around the person taking immunosuppressants.(mdcalc.com)

FAQs

Can vaccines trigger a Crohn’s or UC flare?

Across multiple studies and meta‑analyses, flare rates after recommended inactivated vaccines (flu, pneumococcal, hepatitis B, shingles) are low and similar to background flare rates.(pubmed.ncbi.nlm.nih.gov)
Current evidence supports that these vaccines are safe for adults with IBD, including those on immunosuppressants.

Should biologic or other IBD medicines be stopped around vaccination?

For inactivated vaccines, guidelines generally do not recommend routinely stopping biologics or other IBD medicines, because that may risk a flare.(pubmed.ncbi.nlm.nih.gov)
Live vaccines, if ever considered, require careful planning and temporary changes in therapy under specialist guidance.(academic.oup.com)

What if important vaccines were missed before starting immunosuppressants?

Most inactivated vaccines can still be given while on immunosuppressive treatment, although responses may be slightly weaker.(gastro.org)
Decisions about live vaccines usually change once treatment has begun, so clinicians rely instead on non‑live options and infection‑prevention measures.

Why is household vaccination discussed in IBD visits?

Family members and close contacts can bring infections like flu, COVID‑19, or whooping cough into the home.
Keeping them fully vaccinated lowers everyone’s infection risk and is specifically recommended in preventive‑care guidelines for patients on immunosuppressive therapy.(pubmed.ncbi.nlm.nih.gov)