Hepatitis A-B Vaccine

What Is Hepatitis A/B Vaccine Used For and How Does it Work?

Hepatitis A/B vaccine is used for hepatitis A & B immunization.

Hepatitis A/B vaccine is available under the following different brand names: Twinrix.

What Are the Dosages of Hepatitis A/B Vaccine?

Hepatitis A/Hepatitis B Viruses

Intramuscular (IM) suspension

  • (720 ELISA units/20mcg)/1mL

Dosage Considerations – Should be Given as Follows:

Hepatitis A & B Immunization

  • Standard dosing: 1 mL intramuscularly (IM) at 0, 1, and 6 months
  • Accelerated dosing: 1 mL IM on days 0, 7, and 21-30, followed by a 4th dose at 12 months
  • Safety and efficacy not established in pediatric patients under 18 years

Other Information

Up-to-date vaccination schedules are available at http://www.cdc.gov/vaccines/schedules/hcp/index.html

What Are Side Effects Associated with Using Hepatitis A/B Vaccine?

Suspected adverse events after administration of any vaccine may be reported to Vaccine Adverse Events Reporting System (VAERS), 1-800-822-7967

Side effects of Hepatitis A/B Vaccine may include:

  • Soreness
  • Headache
  • Fatigue
  • Redness
  • Diarrhea
  • Nausea
  • Fever
  • Swelling

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Hepatitis A/B Vaccine?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

Severe interactions of hepatitis a/b vaccine include:

  • belimumab

Hepatitis A/B Vaccine has serious interactions with at least 36 different drugs.

Moderate interactions of hepatitis a/b vaccine include:

Mild interactions of hepatitis a/b vaccine include:

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Hepatitis A/B Vaccine?


This medication contains the hepatitis a/b vaccine. Do not take Twinrix if you are allergic to hepatitis a/b vaccine or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • Hypersensitivity to yeast

Effects of Drug Abuse

  • No information is available.

Short-Term Effects

  • See "What Are Side Effects Associated with Using Hepatitis A/B Vaccine?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Hepatitis A/B Vaccine?"


  • Contains thimerosal (less than 1 mcg mercury)

Pregnancy and Lactation

Use hepatitis a/b vaccine with caution during pregnancy if benefits outweigh risks. Animal studies show risk and human studies are not available or neither animal nor human studies were done.

It is not known if the hepatitis a/b vaccine is excreted in breast milk. Consult your doctor before breastfeeding.


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