Immunization against Hepatitis B Surface Antigen (HBsAg) in a Cohort of Nursing Students Two Decades after Vaccination: Surprising Feedback

Health-care students can be exposed to biological risks during university training. The persistence of long-term immunogenicity against hepatitis B virus (HBV) was analyzed in a cohort of nursing students two decades after primary vaccination. A total of 520 students were enrolled at the University of Palermo and were evaluated for levels of anti-HBsAg antibodies. ThestudentswereexaminedduringthefirstyearoftheirDegreeCourseandwerecheckedtwoyears later. All students with anti-HBsAg <10 mIU/mL during their first or third year were boosted within onemonth. Theproportionofstudentsthatwerevaccinatedduringadolescenceshowinganti-HBsAg ≥10 mIU/mL was higher than that observed in students who were vaccinated during infancy (69% versus31.7%;p-value<0.001). ReceivingHBVvaccinationatadolescencewassignificantlyassociated with a fourfold increased possibility of having anti-HBsAg titers≥10 mIU/mL (adj-OR = 4.21, 95% CI: 2.43–7.30). Among the students who were checked at the third year and boosted after the first year (n = 279), those who were vaccinated during infancy showed a higher percentage of antibody titers <10 mIU/mL (20.3% versus 8.7% among vaccinated during adolescence; p < 0.01). This study confirms that HBV vaccination at adolescence might determine a higher long-term persistence of anti-HBsAg titers≥10 mIU/mL and that anti-HBV booster could increase levels of anti-HBsAg over a relatively short period, especially in subjects who were vaccinated during infancy.