Is there a hepatitis A and B vaccine and what is the schedule?

Hepatitis A and B Combination Vaccine and Vaccination Schedule

Yes, there is a combination hepatitis A and B vaccine called Twinrix, which is administered in a standard 3-dose schedule at 0,1, and 6 months for adults aged 18 years and older.

Combination Vaccine Options

Twinrix is the only licensed combination vaccine that provides protection against both hepatitis A and hepatitis B viruses in the United States. It contains:

• 720 ELU of hepatitis A antigen (half of the adult Havrix dose)
• 20 μg of recombinant hepatitis B surface antigen (same as the adult Engerix-B dose) 1

Standard Vaccination Schedule

For adults aged ≥18 years, Twinrix is administered as:

• Standard schedule: 3 doses at 0,1, and 6 months 2
• Accelerated schedule: 4 doses at 0,7,21-30 days, and a booster at 12 months 2, 3

The accelerated schedule provides faster protection for those who need it quickly, such as travelers or those with imminent risk of exposure 3.

Efficacy and Immunogenicity

After completion of the 3-dose Twinrix series:

• Antibody responses to both antigens are equivalent to responses seen after single-antigen vaccines administered separately 1
• Nearly 100% of vaccinees develop protective antibodies against hepatitis A 4

• 95% develop protective antibodies against hepatitis B 4

• Protection has been demonstrated to persist for at least 4 years in follow-up studies 4

Single-Antigen Vaccine Options

If the combination vaccine is not available or appropriate, single-antigen vaccines can be used:

Hepatitis A Vaccines:

• Havrix:
  • Ages 12 months-18 years: 720 ELU per dose (0.5 mL) in a 2-dose schedule
  • Ages >18 years: 1,440 ELU per dose (1.0 mL) in a 2-dose schedule 1
• Vaqta:
  • Ages 12 months-18 years: 25 U per dose in a 2-dose schedule
  • Ages >18 years: 50 U per dose in a 2-dose schedule 1

Hepatitis B Vaccines:

• Recombivax HB:
  • Ages 11-15 years: 10 μg (1.0 mL) in a 2-dose schedule
  • Ages 11-19 years: 5 μg (0.5 mL) in a 3-dose schedule
  • Ages ≥20 years: 10 μg (1.0 mL) in a 3-dose schedule 1
• Engerix-B:
  • Ages 11-19 years: 10 μg (0.5 mL) in a 3-dose schedule
  • Ages ≥20 years: 20 μg (1.0 mL) in a 3-dose schedule 1
• Heplisav-B:
  • Ages ≥18 years: 20 μg (0.5 mL) in a 2-dose schedule at 0 and 1 month 2

Special Considerations

1. Age limitations: Twinrix is only licensed for adults aged ≥18 years in the United States 1

2. Interrupted schedules: If the vaccination schedule is interrupted, it does not need to be restarted. The series should be continued with remaining doses administered with appropriate spacing 2

3. Immunocompromised individuals: May have reduced response to vaccination. Consider:

   • Higher doses for hemodialysis patients and other immunocompromised persons
   • Post-vaccination serologic testing for high-risk groups 2

4. Factors affecting response: Age >40 years, smoking, obesity, and immunosuppression can reduce vaccine response 2

Practical Advantages of Combination Vaccine

Using Twinrix offers several advantages:

• Fewer injections for protection against two infections
• Better compliance with vaccination schedule
• Lower implementation costs
• Fewer missed vaccination opportunities 5

Common Pitfalls to Avoid

1. Incorrect dosing: Ensure the correct formulation is used based on age and condition

2. Inadequate storage: Store vaccines at 35.6°F-46.4°F (2°C-8°C); do not freeze 1

3. Inappropriate route: Always administer intramuscularly into the deltoid muscle using appropriate needle length 1

4. Assuming immunity without testing: For high-risk individuals, consider post-vaccination serologic testing 1-2 months after the final dose to confirm protection 2

5. Missing the accelerated schedule booster: The 12-month booster is essential for long-term protection when using the accelerated schedule 3