The durability of anti-HBs following hepatitis B vaccination on a two-dose schedule vs a three-dose schedule in adults is still debatable. Adults were followed up 12 years after receiving their initial vaccination in this research. Three hundred forty-one and 288 adults between the ages of 15 and 40 were vaccinated against HBV on a 0-, 1-, and 6-month schedule, or on a 0- and 6-month schedule, respectively. Blood samples were obtained from 202 patients on a 0-, 1-, and 6-month regimen and 194 patients on a 0- and 6-month regimen one month and twelve years after the initial series, and anti-HBs levels were assessed. The seroprotection rates for the 3-dose schedule and the 2-dose ones were 71.78 percent and 53.61 percent, respectively. Anti-HB GMCs were 31 mIU/mL and 12 mIU/mL, respectively. Participants who used three dosages had a greater rate of seroprotection and GMC. Multivariable analysis revealed that patients with anti-HBs titers of 100 mIU/ml shortly after the primary series had a greater likelihood of anti-HBs levels at follow-up than those with titers of 10 mIU/ml and 10–100 mIU/ml. 

In conclusion, people who had HepB primary vaccination on a 0-, 1-, and 6-month schedule may have longer anti-HBs persistence than those who received HepB immunization on a 0-, 6-month schedule, while good anti-HBs persistence could be attained following HepB immunization on both schedules.