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

When you’re taking a biologic for rheumatoid arthritis, psoriasis, or Crohn’s disease, the goal is to quiet your overactive immune system. But that same suppression makes you more vulnerable to infections-some serious, some preventable. The data doesn’t mince words: patients on biologics face a 2.1 times higher risk of being hospitalized for an infection compared to those on traditional treatments. That’s not a small bump. It’s a red flag that demands action.

Why Biologics Increase Infection Risk

Biologics aren’t like regular pills. They’re made from living cells and target specific parts of your immune system. TNF inhibitors like adalimumab and infliximab block a key inflammatory signal, but that same signal also helps your body fight off bacteria and viruses. Without it, your defenses weaken. The result? Respiratory infections-like pneumonia and bronchitis-make up nearly half of all serious infections in biologic users. Fungal infections like candidiasis rise with IL-17 inhibitors. And herpes zoster (shingles) becomes far more common with JAK inhibitors.

Not all biologics carry the same risk. TNF blockers are the most scrutinized, responsible for about 68% of prescriptions. But newer agents like ustekinumab (an IL-12/23 inhibitor) show significantly lower infection rates. Certolizumab pegol, because of its unique structure, has a 18% lower risk of respiratory infections than other TNF inhibitors. The takeaway? Your choice of drug matters. But even the safest biologic still needs careful management.

Screening Before You Start: The Non-Negotiable Steps

Starting a biologic without screening is like driving without checking your brakes. Three tests are mandatory before your first dose:

• HBsAg - checks for active hepatitis B
• HBcAb - detects past exposure to hepatitis B
• HBsAb - confirms immunity from vaccination or prior infection

If HBcAb is positive-even if HBsAg is negative-you have latent hepatitis B. Without preventive treatment, there’s a 27.6% chance of viral reactivation. That can lead to liver failure. The CDC and AASLD require HBV DNA testing in these cases. Many clinics miss this step. In fact, 41% of reported screening errors involve skipping HBcAb or HBV DNA testing.

Tuberculosis screening is another critical checkpoint. Interferon-gamma release assays (IGRAs) are preferred over the old skin test because they’re more accurate. But here’s the catch: in low-TB areas, IGRA positivity doesn’t always mean active disease. Some experts argue over-screening leads to unnecessary treatment. Still, guidelines are clear: if you’re starting a biologic, you get tested. Period.

Vaccinations: Timing Is Everything

You can’t get vaccinated while on a biologic and expect full protection. Your immune system is too suppressed. So you have to do it before you start.

• Live vaccines (MMR, varicella, nasal flu) - must be given at least 4 weeks before your first biologic dose
• Inactivated vaccines (flu shot, pneumococcal, hepatitis B, Shingrix) - give at least 2 weeks before

Shingrix, the shingles vaccine, is especially important. Nearly 1 in 5 biologic users get shingles without it. And if you’ve already had chickenpox, you’re at risk-even if you never knew it. Serology testing for VZV IgG is recommended. If your level is below 140 mIU/mL, you need the vaccine.

Don’t forget pneumococcal vaccines. Pneumonia is the leading cause of biologic-related hospitalizations. The CDC recommends both PCV20 and PPSV23, spaced at least a year apart. Antibody levels should be checked after vaccination. If your opsonophagocytic activity is below 1:8, you may need a booster.

Who’s at Highest Risk?

Not everyone faces the same danger. Your risk spikes if:

• You’re over 50 - each decade adds 37% more infection risk
• You’re on prednisone or another steroid at more than 10mg/day - that alone multiplies your risk by 2.3x
• You have diabetes, COPD, or chronic kidney disease - each raises your odds by 1.9 to 2.4 times

Patients with these conditions need extra vigilance. A 65-year-old with type 2 diabetes and COPD on adalimumab isn’t just at higher risk-they’re in the danger zone. Their care plan should include not just screening and vaccines, but also education on early infection signs: fever, cough, fatigue, or even mild skin redness.

What Patients Are Really Experiencing

Real stories show the gap between guidelines and reality. One patient on MyTherapy wrote: “My pre-biologic workup at Mayo Clinic caught my latent TB. They treated me for 9 months. I’ve been on Humira for 3 years-zero infections.” That’s the ideal.

Another on HealthUnlocked said: “My GI doctor started Stelara without checking my vaccines. Four months later, I got shingles.” That’s the reality for too many. A 2023 survey found that 63% of patients reported at least one screening or vaccination omission. The most common? Missing HBV core antibody testing and not checking VZV immunity.

The good news? Patients who received a full CDC 12-point infection prevention checklist had a 78% rate of zero serious infections-compared to just 43% without education.

What You Need to Do Right Now

If you’re about to start a biologic-or already on one-here’s your action list:

1. Request full hepatitis B screening: HBsAg, HBcAb, HBsAb. If HBcAb is positive, demand HBV DNA testing.
2. Review your vaccine record. If you’ve never had chickenpox or the varicella vaccine, get it now-before starting.
3. Get Shingrix if you’re over 50, even if you’ve had shingles before.
4. Get pneumococcal vaccines (PCV20 and PPSV23) if you haven’t already.
5. Ask your doctor: “Am I on a high-risk biologic? Do I need prophylaxis?”
6. Keep a personal health log: dates of vaccines, screening results, and any infections.

What’s Changing in 2025 and Beyond

The rules are tightening. The FDA now requires real-world evidence of infection risk reduction for any new biologic label expansion. The CDC’s updated BMBL 7th Edition, coming in October 2025, will include specific safety protocols for biologic users-like standardized PPE guidelines for healthcare workers handling these drugs.

AI tools like the Cerner Biologics Safety Algorithm are now being used in major hospitals to predict individual infection risk using 87 clinical variables. And by 2026, Medicare will tie 15% of biologic payments to whether clinics documented proper screening and vaccination.

The message is clear: safety isn’t optional. It’s the foundation.

Frequently Asked Questions