Accelerated Twinrix Regimen for Rapid Hepatitis A and B Protection

Introduction to the Accelerated Regimen

The Centers for Disease Control and Prevention recommends an accelerated 4-dose regimen for Twinrix, a combined hepatitis A and B vaccine, for adults ≥18 years who need rapid protection against both hepatitis A and B viruses, with a dosing schedule of 0, 7, 21-30 days, and a 12-month booster 1, 2

The accelerated regimen consists of 4 doses, with the third dose given between days 21-30, and a booster dose at 12 months, with each dose containing 720 EL.U of inactivated hepatitis A antigen and 20 μg of recombinant hepatitis B surface antigen (HBsAg) in 1.0 mL 1, 2, 3
The standard 4-day grace period for vaccine intervals does not apply to the first three doses of Twinrix when using the accelerated schedule, requiring doses to be given on the exact days specified (0, 7, and 21-30 days) 1, 2, 4

The American College of Physicians and the Centers for Disease Control and Prevention recommend the accelerated schedule for adults requiring rapid protection due to imminent exposure risk, such as last-minute travelers to hepatitis A/B endemic regions 4
The vaccine is contraindicated in pregnant women, who should use Engerix-B or Recombivax HB instead, and in children <18 years, as it is not approved for this age group 1, 2, 3, 5

The vaccine is also contraindicated in hemodialysis patients due to insufficient safety and efficacy data 3