N=2152 | ||
Age, years, median (IQR) | 35 (30–42) | |
Age classes, n (%) | Young adulthood (below 39 years) | 1432 (66.54) |
Middle adulthood (40–59 years) | 683 (31.74) | |
Old age (above 60 years) | 37 (1.72) | |
Born from 1979 onwards, n (%) | 1612 (74.91) | |
Gender, n (%) | ||
Men | 2108 (97.96) | |
Women | 25 (1.16) | |
Transgender women | 19 (0.88) | |
Foreign born, n (%) | 379 (17.61) | |
Chemsex user, n (%) | Yes | 105/1749 (6.00) |
Missing | 403 | |
HBsAg positive, n (%) | 10 (0.46) | |
Previous HBV infection (with or without anti-HBs>10 mUI/mL), n (%) | 133 (6.18) | |
Already vaccinated for HBV, n (%) | 1734 (80.58) | |
Vaccinated after mandatory immunisation law in 1991*, n (%) | 1281 (59.53) | |
1979–1991 cohort | 888 (69.32) | |
1992 onwards cohort | 393 (30.68) | |
Vaccinated individuals who needed a booster injection, n (%) | 488/1734 (28.14) | |
Eligible† for HBV vaccination, n (%) | 284 (13.20) | |
Individuals who started HBV vaccination after PrEP consultation, n (%) | 104/284 (36.62) | |
Non-responder to primary and secondary immunisation courses, n (%) | 14/1794 (0.78) |
Exceptions: One subject with positive HBsAg was vaccinated within the 1979–1991 cohort and acquired the infection through sexual contact; eight individuals with anti-HBs/anti-HBc positive titres were vaccinated after mandatory immunisation law in 1991.
*Mandatory immunisation law of 1991 established that HBV vaccination should have been done at birth for those born from 1992 onwards and at 12 years for those born from 1979 to 1991. This approach extended the HBV vaccination coverage on all the young people of less than 25 years in a 12-year period.
†People born in Italy before 1 January 1979 or abroad with no evidence of previous vaccination or HBsAg+ or HBcAb+.
HBcAb, antibodies againts hepatitis B core antigen; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; PrEP, pre-exposure prophylaxis.