Research Information System
IRISH JOURNAL OF MEDICAL SCIENCE, vol.195, no.1, pp.243-254, 2026 (SCI-Expanded, Scopus)
Introduction We aimed to determine the antibody response of intradermal (ID) plus intramuscular (IM) recombinant hepatitis B vaccination in individuals with inadequate immune response despite vaccination. Methods This single-center, retrospective study included individuals aged >= 18 years who had previously completed the primary 3-dose vaccination course for hepatitis B and had anti-HBs titers <10 mlU/ml. Participants were administered a double dose of recombinant hepatitis B vaccine (5 microgram ID+35 microgram IM) at months 0, 1, and 6. Quantitative anti-HBs titers were assessed at months 2 and 7. Vaccination response was categorized as unresponsive (anti-HBs<10 mlU/ml), weak (anti-HBs=10-100 mlU/ml), moderate (anti-HBs=101-1000 mlU/ml), and strong (anti-HBs>1000 mlU/ml). Results A total of 43 individuals were included. After the 2nd and 3rd doses of vaccination, protective antibody responses (anti-HBs>10 mlU/ml) were obtained 81.3% (27.9% weak response, 16.3% moderate response, 37.2% strong response) and 93% (16.3% weak response, 27.9% moderate response, 48.8% strong response), respectively. Anti-HBs antibody titers increased from 505 +/- 501 in the 2nd vaccination to 666 +/- 469 in the 3rd vaccination (p=0.003). After the 3rd dose of vaccination, protective antibody responses inreased from 86.7% to 100% in PLwHIV, from 69.2% to 76.9% in patients with rheumatic diseases, and from 91.7% to 100% in immunocompetent individuals compared to the second dose of vaccination. No antibody response was achieved in any of the patients using rituximab. Conclusion ID (5 mu g) plus IM (35 mu g) recombinant hepatitis B vaccine is promising as an alternative vaccination method in various specific populations, which unresponsive to standard vaccination, such as PLwHIV, immunocompetent patients, and immunomodulator users.