Decrease in Anti-HBs Antibodies over Time in Medical Students and Healthcare Workers after Hepatitis B Vaccination

Area of Science:

• Occupational Health
• Immunology
• Vaccinology

Background:

• Hepatitis B poses a significant occupational risk to healthcare workers (HCWs).
• Assessing immunity levels post-vaccination is crucial for protecting HCWs.
• Understanding the duration of vaccine efficacy is vital for public health strategies.

Purpose of the Study:

• To quantify anti-HBs antibody titres in vaccinated medical students and HCWs.
• To investigate the relationship between time since hepatitis B vaccination and antibody levels.
• To determine the seroprotection rates at various intervals post-vaccination.

Main Methods:

• A cross-sectional study involving 340 medical students and HCWs.
• Inclusion criteria: completed all three hepatitis B vaccine doses and at least six months post-vaccination.
• Anti-HBs titres measured using ELISA on collected blood samples.

Main Results:

• Antibody titres significantly declined with increasing duration post-vaccination.
• After 5 years, 20% of subjects had titres below protective levels (>10 mIU/ml).
• After 10 years, 27% of subjects showed decreased antibody titres, indicating reduced protection.

Conclusions:

• A notable proportion of vaccinated individuals, particularly HCWs, lose protective immunity over time.
• The findings suggest a waning immune response to the hepatitis B vaccine.
• Mandatory booster doses for healthcare professionals are recommended to ensure sustained protection.