Table 5. Methodology for the calculation of the annual number of acute hepatitis B cases, by age group, in the no-vaccination scenario.

No-vaccination scenario: slow decrease of acute hepatitis B incidence
0–14 y (reduction of incidence mainly due to adoption of preventive interventions other than vaccination)
75% of calculated cases = same incidence of vaccination period
25% of calculated cases = incidence of 1991

15–24 y
50% of calculated cases = same incidence of vaccination period
50% of calculated cases = incidence of 1991 (intermediate importance of sexual transmission)

≥ 25 y
25% of calculated cases = same incidence of vaccination period
75% of calculated cases = incidence of 1991 (maximal importance of sexual transmission)