Before Starting Anti-TNF for Crohn’s: TB/Hep B Screening + Vaccine Checklist
Last Updated Jan 15, 2026
Starting an anti-tumor necrosis factor (anti-TNF) biologic for Crohn’s disease can feel like a big step. Because anti-TNF medicines lower parts of the immune response, many clinics use a standard “safety first” process before the first dose, especially for infections that can wake up again (reactivate) when immunity is lowered. The checklist below is meant to support organized prep and clearer conversations with the gastroenterology team.
Screening checklist: TB and hepatitis B (and why it matters)
Tuberculosis (TB) and hepatitis B are two key infections to check before anti-TNF therapy because both can be silent for years and then become active when the immune system is suppressed. Anti-TNF labels include warnings about serious infections, and commonly call for TB testing before treatment (and monitoring during treatment) and hepatitis B testing before starting a TNF blocker. [1]
TB test before biologics (Crohn’s):
- Ask which TB test is being used: a TB blood test (interferon-gamma release assay, also called IGRA) or a TB skin test (tuberculin skin test).
- Know why the method matters: CDC notes either test is acceptable, and TB blood tests are often preferred in some situations (for example, prior Bacille Calmette-Guérin vaccination, or if returning for a reading is hard). [2]
- Plan for “next steps” if a test is positive: clinicians typically evaluate for active TB (often including a symptom review and chest imaging) and discuss treatment for latent TB infection before starting medicines that suppress immunity.
Hepatitis B screening (often a “triple panel”):
- Many clinicians use a triple panel blood test: hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs), and total antibody to hepatitis B core antigen (total anti-HBc). This approach can help identify current infection, past infection (which may be at risk of reactivation during immunosuppression), or lack of immunity. [3]
Questions to bring to the visit
- “Which TB test is planned, and will anything else be needed if it is positive?”
- “Was hepatitis B testing done with the triple panel, and what do the results mean for timing?”
- “If past hepatitis B infection is found, who helps coordinate next steps (gastroenterology, primary care, infectious disease, hepatology)?”
Vaccine checklist and timing before anti-TNF
A practical goal is to review vaccine records early, since some vaccines work best when given before immune suppression, and some (live vaccines) are usually avoided once immune suppression starts. This is the heart of “vaccines before biologics Crohn’s” planning.
Timing basics (often used when there is time to plan):
CDC guidance notes that, when initiating immunosuppressive therapy, providers often wait 4 weeks after a live vaccine and 2 weeks after a non-live vaccine. It also notes that therapy for chronic inflammatory conditions may not be delayed just because of prior vaccination, so timing is individualized. [4]
Common immunizations to review before anti-TNF (examples):
- Influenza (flu) vaccine every year (non-live injection), and avoidance of the live nasal spray option when immunosuppressed.
- Pneumococcal vaccination (to help prevent serious pneumonia and bloodstream infections).
- Hepatitis B vaccination if not immune.
- Recombinant shingles vaccine (Shingrix, non-live) for eligible adults.
- Human papillomavirus (HPV), tetanus-diphtheria-pertussis (Tdap/Td), and COVID-19 vaccines as appropriate for age and health status.
- Live vaccines to discuss early if not immune (for example, measles-mumps-rubella or varicella), since these may require special timing considerations. [5]
Quick appointment questions
- “Which vaccines are recommended before the first dose, and which can wait?”
- “Are any vaccines live, and does timing affect the start date?”
- “Can the gastroenterology team help coordinate vaccines with primary care or a pharmacy (and document them in the chart)?”