What are the recommended hepatitis A and B vaccination schedules for a healthy adult with no underlying medical conditions to ensure immunity?

Hepatitis Vaccination and Immunity for Healthy Adults

For a healthy adult with no underlying medical conditions, hepatitis B vaccination should be administered as a 2-dose series of Heplisav-B at 0 and 1 month, or alternatively as a 3-dose series of Recombivax HB (10 μg) or Engerix-B (20 μg) at 0,1, and 6 months; hepatitis A vaccination should be given as a 2-dose series at 0 and 6-12 months (Havrix) or 0 and 6-18 months (Vaqta). 1, 2, 3

Hepatitis B Vaccination Schedule

Standard Options for Healthy Adults

• The 2-dose Heplisav-B regimen (20 μg at 0 and 1 month) is the most convenient option for adults ≥18 years, providing faster protection with fewer visits. 1, 2

• The traditional 3-dose series remains highly effective: Recombivax HB 10 μg (1.0 mL) or Engerix-B 20 μg (1.0 mL) administered at 0,1, and 6 months for adults ≥20 years. 1, 3

• After the first dose, only 30-55% achieve protective antibody levels (anti-HBs ≥10 mIU/mL); after the second dose, 75% are protected; after the third dose, >90% achieve protection. 3

• Vaccine-induced immunity persists for >30 years, and routine booster doses are not needed in immunocompetent adults. 3

Critical Timing Principles

• If the vaccination schedule is interrupted, never restart the series—simply continue where you left off. 1, 2

• Minimum intervals must be respected: 4 weeks between doses 1 and 2,8 weeks between doses 2 and 3, and 16 weeks between doses 1 and 3. 1, 2

• There is no maximum interval between doses—delayed doses do not require restarting the series. 2

• Doses administered ≤4 days before the minimum interval are considered valid. 1

Hepatitis A Vaccination Schedule

Standard Regimen

• Single-antigen vaccines should be administered as a 2-dose series: Havrix at 0 and 6-12 months, or Vaqta at 0 and 6-18 months. 4

• The first dose provides substantial protection, but the second dose is essential for long-term immunity. 4

Who Should Receive Hepatitis A Vaccine

• Any person seeking protection from hepatitis A virus infection should be vaccinated—identification of specific risk factors is not required. 4

• Specific high-risk groups include: men who have sex with men, persons who use injection or non-injection illicit drugs, travelers to countries with high or intermediate HAV endemicity, persons with chronic liver disease, and persons who receive clotting factor concentrates. 4

Combined Hepatitis A and B Vaccination (Twinrix)

Standard and Accelerated Schedules

• Twinrix can be administered as a 3-dose series at 0,1, and 6 months for adults ≥18 years seeking protection against both hepatitis A and B. 4, 1

• An accelerated 4-dose schedule is available for those requiring rapid protection: doses at 0 days, 7 days, 21-30 days, and a booster at 12 months. 4, 1, 2

• The accelerated schedule provides earlier seroprotection but requires the fourth dose at 12 months for long-term immunity. 1

• At month 2 of the standard schedule, >99% of vaccinees are seropositive for anti-HAV and 84% are protected against hepatitis B; after the third dose, nearly all have protective titers against both viruses. 5

Pre-Vaccination Testing Considerations

• Pre-vaccination serologic testing is not required and should not be a barrier to vaccination in healthy adults. 1

• However, testing for prior immunity (HBsAg, anti-HBs for hepatitis B; total anti-HAV for hepatitis A) can be cost-effective in certain populations: older adults, foreign-born individuals, African Americans, and those with potential prior exposure. 6

• Testing for hepatitis B surface antigen (HBsAg) and antibodies to HBsAg (anti-HBs) is the most efficient screening method, as HBsAg identifies active infection and anti-HBs identifies immunity. 6

Post-Vaccination Testing

• Post-vaccination serologic testing is not routinely recommended for healthy adults after hepatitis A vaccination, as seroconversion rates approach 100%. 6

• Post-vaccination testing for hepatitis B is not routinely needed in healthy immunocompetent adults, as >90% achieve protective antibody levels after completing the series. 3, 6

Common Pitfalls to Avoid

• Do not restart the vaccination series if doses are delayed—there is no maximum interval between doses; simply continue the schedule. 1, 2

• Do not assume that pre-vaccination testing is mandatory—it should not delay vaccination in healthy adults without obvious prior exposure. 1

• Do not use Heplisav-B or PreHevbrio in pregnant women, as these vaccines lack sufficient safety data in pregnancy; use Engerix-B, Recombivax HB, or Twinrix instead. 1, 2

• Do not administer the final hepatitis B dose before 24 weeks of age in infants, though this is not relevant for adult vaccination. 2, 3

Special Considerations for Older Adults

• Elderly travelers (>50 years) may have reduced seroprotection after a single dose of hepatitis A vaccine (approximately 65%), but seroprotection reaches 98% after the booster dose. 7

• Consider screening elderly travelers for naturally acquired HAV immunity before vaccination, and if susceptible, immunize well in advance to allow time for post-vaccination testing or a second dose. 7