High Rates of Seroprotection to Hepatitis B After a Hepatitis B Challenge Dose in Previously Vaccinated Patients with Inflammatory Bowel Disease on Immunosuppressive Therapy.

Background: Healthy populations have high rates of sustained vaccine-induced seroprotection to hepatitis B virus, but previous studies in immunosuppressed patients with inflammatory bowel disease (IBD) have shown suboptimal seroprotection rates. A challenge dose of hepatitis B vaccine (HepB) is recommended in previously vaccinated individuals who are seronegative to elicit an anamnestic response and determine if they are seroprotected. The aim of our study was to determine sustained seroprotection rates to hepatitis B vaccine (HepB) in patients with IBD.

Methods: This was a single-center prospective study of patients with IBD previously vaccinated with a three dose HepB series. Patients had a hepatitis B surface antibody (anti-HBs) drawn; if it was below 10 mIU/mL, they received a challenge dose of the HepB vaccine to assess for anamnestic response and sustained seroprotection. The primary outcome was to determine the rate of sustained seroprotection (anti-HBs ≥ 10).

Results: A total of 168 patients met inclusion criteria, mean age 35.7 years ± 13.6 standard deviation (SD). Initially 120 (71.4%) had anti-HBs ≥ 10 mIU/mL, with median anti-HBs of 37 mIU/mL (interquartile range 0-234); 48 (28.6%) needed a challenge dose, of which 34 responded with anti-HBs ≥ 10 mIU/mL. In total, 154 (91.7%) demonstrated sustained seroprotection to HepB. Those not seroprotected were more likely to have been vaccinated on immunosuppressive therapy or after their diagnosis of IBD.

Conclusions: Most vaccinated patients with IBD maintain sustained seroprotection to HepB despite prolonged exposure to immunosuppression. This contradicts prior studies and shows that immunosuppression does not lead to loss of seroprotection.