Biologics Safety: Infection Risk, Screening, and Vaccination Guidance for Autoimmune Patients

When you’re managing an autoimmune disease like rheumatoid arthritis, psoriasis, or Crohn’s disease, biologics can change your life. These drugs-monoclonal antibodies and fusion proteins-target specific parts of your immune system to calm inflammation. But there’s a trade-off: biologics suppress your body’s natural defenses, making you more vulnerable to infections. That’s not just a theoretical risk. Studies show people on biologics have more than double the chance of being hospitalized for an infection compared to those on traditional treatments. The good news? This risk isn’t random. It’s predictable. And with the right steps, it’s manageable.

Why Biologics Increase Infection Risk

It’s not just the drug. Your body matters too. If you’re over 50, your infection risk climbs 37% every decade. If you’re on prednisone at 10mg or more per day, your risk jumps 2.3 times. Diabetes? That adds nearly double the risk. Chronic lung or kidney disease? Same thing. These aren’t minor factors-they’re major red flags that change how you start treatment.

Screening Before You Start

For hepatitis B, you need all three markers: HBsAg (surface antigen), HBsAb (surface antibody), and HBcAb (core antibody). Why all three? Because some people have hidden, inactive HBV. If you’re HBcAb positive-even if HBsAg is negative-there’s still an 8.7% chance you carry hidden virus. Without treatment, starting a biologic can trigger a deadly reactivation in up to 27.6% of these cases. That’s why guidelines now require HBV DNA testing for anyone who’s HBcAb positive. If the virus is active, you need antiviral drugs like entecavir before even thinking about biologics.

Tuberculosis screening is trickier. Most clinics use an IGRA blood test, which is 98% specific. But in low-risk areas, this test can give false positives. One study in Alabama found that 12.7% of patients tested positive for latent TB, yet only 0.8 cases per 100 patient-years actually developed active disease. That means many people get unnecessary treatment. Still, most guidelines stick with IGRA because the cost of missing a case is too high.

For chickenpox, you need a blood test for VZV IgG. If you’ve never had chickenpox or the vaccine, you’re at risk for a severe case if you start a biologic. That’s why you need the Shingrix vaccine-two doses, 2 to 6 months apart-before starting treatment. Don’t wait. Once you’re on a biologic, you can’t get live vaccines anymore.

Vaccination Rules You Can’t Ignore

For hepatitis B, you need proof you’re protected. After the vaccine series, your anti-HBs level must be at least 10 mIU/mL. If it’s lower, you’ll need a second series. For VZV, your IgG level must be ≥140 mIU/mL. If you’re not protected, get Shingrix, not the old Zostavax. Shingrix is 90% effective, even in older adults.

Don’t forget pneumococcal vaccines. You need both PCV20 and PPSV23, given at least a year apart. If you’ve already had PPSV23, wait a year before giving PCV20. If you haven’t had either, give PCV20 first, then PPSV23 after a year.

And yes, get your flu shot every year. Even though it’s not 100% effective, it cuts your risk of serious lung infections by up to 40%. The CDC recommends the high-dose version for people over 65.

What to Avoid and Who Should Skip Biologics

Some biologics are riskier than others. TNF inhibitors are generally avoided in people with heart failure, multiple sclerosis, or a history of skin cancer. IL-17 inhibitors like secukinumab carry a higher risk of candidiasis-yeast infections in the mouth or genitals. JAK inhibitors, though not technically biologics, are often grouped with them and raise herpes zoster risk by 33% compared to TNF blockers.

There’s also a growing group of patients who don’t respond well to biologics. If you’ve had multiple infections while on one drug, switching to another might not help. Sometimes, stepping back to traditional DMARDs like methotrexate is safer.

Real-World Mistakes and How to Avoid Them

Another problem? Poor coordination. One patient got started on Stelara without anyone checking her vaccine records. Four months later, she got shingles. Another patient’s doctor didn’t test for latent TB until after the first dose. She spent nine months on TB treatment before restarting her biologic.

The fix? Ask for a checklist. The CDC has a 17-point safety checklist used in sentinel labs. It covers everything from HBV testing to pneumococcal vaccine timing. If your doctor doesn’t use it, ask why. You’re not being difficult-you’re protecting your health.

Patients who received full pre-treatment education-like the CDC’s 12-point infection prevention guide-were 78% more likely to go a year without a serious infection. That’s not a small difference. That’s life-changing.

What’s Changing in 2025 and Beyond

Insurance is catching up too. Starting in 2026, Medicare will tie 15% of biologic payments to whether clinics followed safety protocols. That’s going to push even small practices to adopt checklists and electronic reminders.

Technology is helping. AI tools like the Cerner Biologics Safety Algorithm now analyze 87 clinical factors-age, lab values, medication history, even geography-to give you a personalized infection risk score. It’s not perfect, but it’s better than guesswork.

And in rural areas, where access is limited, telehealth platforms are now being rolled out to help patients complete screenings remotely. The goal? Cut the 72% gap in safety compliance between urban and rural clinics by 2030.

What You Should Do Today

1. Ask for HBV screening: HBsAg, HBsAb, and HBcAb.
2. Get your VZV IgG level checked. If it’s low, start Shingrix now.
3. Confirm your pneumococcal vaccine status. If you’re unsure, get both PCV20 and PPSV23.
4. Ask if you’ve had a TB test in the last year. If not, get an IGRA.
5. Make sure all vaccines are done at least 2-4 weeks before your first dose.
6. Request a copy of the CDC’s 17-point biologics safety checklist and review it with your doctor.

Don’t assume your doctor knows everything. Many don’t. The 2024 AAMC survey found only 38% of community practices fully follow safety guidelines. You’re your own best advocate. Take control. Ask questions. Keep records. Your next infection might be preventable.