Persistence of protective anti-HBs antibody levels and anamnestic response to HBV booster vaccination: A cross-sectional study among healthcare students 20 years following the universal immunization campaign in Italy

Figures & data

Table 1. Demographic characteristics and anti-Hbs features of Healthcare Students attending the Medical and Pharmaceutical School of the University of Genoa, Italy (Total Vaccinated Cohort).

	n (%)
No of subjects	717 (100)
Age (mean, SD)	24.8 (4.6)
Gender, Female	481 (67.2)
Medical Students	189 (26.4)
Healthcare Professional Students	528 (73.6)
Years since vaccination(mean,SD)	21.35 (3.8)
Vaccinated in infancy	535 (74.6)
Vaccinated in adolescence	182 (25.4)
HBs titer Total Cohort Vaccination ≥ 10 mIU/mL	507 (70.7)

Table 2. Characteristics of vaccinated Health Care Students attending the Medical and Pharmaceutical School of the University of Genoa, Italy, stratified by age at vaccination.

	Vaccinated in infancy n (%)	Vaccinated in adolescence n (%)	p-value
N° of subjects	535	182
Age (mean, SD)	23.2 (1.6)	29.7 (6.8)	< 0.001
Gender, Female	367 (68.6)	114 (62.6)	0.14
Years since vaccination	22.8 (1.7)	17.2 (5.2)	< 0.001
Attending medical school	132 (24.7)	57 (31.3)	0.08
HBs titer ≥ 10 mIU/mL	358 (66.9)	149 (81.9)	< 0.001

Table 3. Characteristics of vaccinated Health Care Students attending the Medical and Pharmaceutical School of the University of Genoa, Italy, stratified by anti-HBs titer.

	HBs titer <10 mIU/mL	HBs titer 10–100 mIU/mL	HBs titer >100 mIU/mL	p-value
No of subjects	210	254	253
Age (mean, SD)	24.4 (5.3)	24.5 (4.1)	25.6 (4.3)	< 0.001
Gender, Female	140 (66.7)	173 (68.1)	168 (66.4)	0.9
Years since vaccination (mean, SD)	22.1(2.9)	21.8 (3.2)	20.3 (4.7)	0.02
Attending medical school	49 (23.3)	58 (22.8)	82 (32.4)	0.02
Vaccinated in infancy	177 (84.3)	201(79.1)	157(62.1)	< 0.001
Vaccinated in adolescence	33 (15.7)	53 (20.9)	96 (37.9)

Table 4. Variables independently associated with seroprotection against HBV among Healthcare Students attending the Medical and Pharmaceutical School of the University of Genoa, Italy.

	Univariate Analysis			Multivariate Analysis
Variable	< 10 IU/L (n = 210) n (%)	≥ 10 IU/L (n = 507) n (%)	P-value	OR (95% CI) ≥ 10 IU/L vs < 10 IU/L	P-value
Age (mean, SD)	24.4 (5.3)	25.1 (4.3)	0.09	0.98 (0.94 – 1.03)	0.4
Gender, Female	140 (66.7)	341 (67.3)	0.88
Years since vaccination (mean, SD)	22.1 (2.9)	21 (4.1)	0.09
Attending medical school	49 (23.3)	140 (27.6)	0.24
Vaccinated in adolescence	33 (15.7)	149 (29.4)	< 0.001	2.57 (1.53 – 4.46)	< 0.001