Confused about Hepatitis B vaccination ?

There are two schedules for Hepatits B vaccination. One is 0, 1, 2 month schedule and the other is 0, 1, 6 month schedule. In the 0, 1, 2 month schedule, three doses are given one month apart. For example if the first dose is given on 23rd March, then the next dose on 23rd April and the third dose on 23rd May. In the 0, 1, 6 month schedule there is a gap of one month between first and second dose; and an interval of 5 months between second and third dose (or we can say an interval of 6 months between first and third dose). Only one booster has been recommended at one year in case of 0,1,2 month schedule. But no booster has been recommended in 0, 1, 6 month schedule.