Twinrix (hepatitis A/B vaccine)

Twinrix (hepatitis A/B vaccine) is a man-made combination vaccine containing an inactivated hepatitis A virus strain and non-infectious hepatitis B virus surface antigen. Inactive Hepatitis A virus combined with hepatitis B antigens stimulates the immune system to develop immunity against hepatitis A and B virus infections. 

Common side effects of Twinrix include

• injection site soreness and pain,
• headache,
• fatigue,
• redness,
• diarrhea,
• nausea,
• fainting, and
• allergic reactions in latex-sensitive people. 

Serious side effects of Twinrix include

• serious allergic reactions,
• abnormal heartbeats, and
• hair loss.

Drug interactions of Twinrix include medications and therapies that suppress the immune system such as

• adalimumab,
• belimumab,
• cyclosporine,
• azathioprine,
• irradiation, and
• high doses of steroids, because suppressing the immune system reduces the effectiveness of Twinrix.

There are no adequate studies done on Twinrix to determine safe and effective use in pregnant women. Twinrix should be given to pregnant women only if clearly needed.

It is unknown if Twinrix enters breast milk; therefore, it is best to be cautious before using it in mothers who are breastfeeding.

Side effects of hepatitis A/B vaccine are

• injection site soreness and pain,
• headache,
• fatigue,
• redness,
• diarrhea,
• nausea, and
• fainting.

The tip caps of pre-filled syringes may contain latex which can cause allergic reactions in latex-sensitive people.

Serious allergic reactions, abnormal heart beats, and hair loss have also been reported.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a vaccine cannot be directly compared with rates in the clinical trials of another vaccine and may not reflect the rates observed in practice.

Following any dose of Twinrix, the most common (≥10%) solicited injection site reactions were

• injection site soreness (35% to 41%) and redness (8% to 11%);
• the most common solicited systemic adverse reactions were
  • headache (13% to 22%) and
  • fatigue (11% to 14%).

The safety of Twinrix has been evaluated in clinical trials involving the administration of approximately 7,500 doses to more than 2,500 individuals.

• In a U.S. study, 773 subjects (aged 18 to 70 years) were randomized 1:1 to receive Twinrix (0-, 1-, and 6-month schedule) or concurrent administration of Engerix-B (0-, 1-, and 6-month schedule) and Havrix (0- and 6-month schedule).
• Solicited local adverse reactions and systemic adverse events were recorded by parents/guardians on diary cards for 4 days (Days 0 to 3) after vaccination.
• Unsolicited adverse events were recorded for 31 days after vaccination.
• Solicited reactions reported following the administration of Twinrix or Engerix-B and Havrix are presented in Table 1.

Table 1: Rates of Local Adverse Reactions and Systemic Adverse Reactions within 4 Days of Vaccination^a with Twinrix^b or Engerix-B and Havrix^c

Most solicited local adverse reactions and systemic adverse reactions seen with Twinrix were considered by the subjects as mild and self-limiting and did not last more than 48 hours.

In a clinical trial in which Twinrix was given on a 0-, 7-, and 21- to 30-day schedule followed by a booster dose at 12 months, solicited local adverse reactions or systemic adverse reactions were comparable to those seen in other clinical trials of Twinrix given on a 0-, 1-, and 6-month schedule.

Among 2,299 subjects in 14 clinical trials, the following adverse reactions were reported to occur within 30 days following vaccination:

Incidence 1% To 10% Of Injections, Seen In Clinical Trials With Twinrix

• Infections and Infestations: Upper respiratory tract infections.
• General Disorders and Administration Site Conditions: Injection site induration.

• Incidence <1% Of Injections, Seen In Clinical Trials With Twinrix

• Infections and Infestations: Respiratory tract illnesses.
• Metabolism and Nutrition Disorders: Anorexia.
• Psychiatric Disorders: Agitation, insomnia.
• Nervous System Disorders: Dizziness, migraine, paresthesia, somnolence, syncope.
• Ear and Labyrinth Disorders: Vertigo.
• Vascular Disorders: Flushing.
• Gastrointestinal Disorders: Abdominal pain, vomiting.
• Skin and Subcutaneous Tissue Disorders: Erythema, petechiae, rash, sweating, urticaria.
• Musculoskeletal and Connective Tissue Disorders: Arthralgia, back pain, myalgia.
• General Disorders and Administration Site Conditions: Injection site ecchymosis, injection site pruritus, influenza-like symptoms, irritability, weakness.

• Incidence <1% Of Injections, Seen In Clinical Trials With Havrix And/Or Engerix-B

• Blood and Lymphatic System Disorders: Lymphadenopathy.^a+b
• Nervous System Disorders: Dysgeusia,^a hypertonia,^a tingling.^b
• Eye Disorders: Photophobia.^a
• Vascular Disorders: Hypotension.^b
• Gastrointestinal Disorders: Constipation.^b
• Investigations: Creatine phosphokinase increased.^a

^a+b Following either Havrix or Engerix-B.
^a Following Havrix.
^b Following Engerix-B.

Adverse reactions within 30 days of vaccination in the U.S. clinical trial of Twinrix given on a 0-, 7-, and 21- to 30-day schedule followed by a booster dose at 12 months were comparable to those reported in other clinical trials.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of Twinrix, Havrix, or Engerix-B. Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to the vaccine.

Postmarketing Experience With Twinrix

• Infections and Infestations: Herpes zoster, meningitis.
• Blood and Lymphatic System Disorders: Thrombocytopenia, thrombocytopenic purpura.
• Immune System Disorders: Allergic reaction, anaphylactoid reaction, anaphylaxis, serum sickness-like syndrome days to weeks after vaccination (including arthralgia/arthritis, usually transient; fever; urticaria; erythema multiforme; ecchymoses; and erythema nodosum).
• Nervous System Disorders: Bell's palsy, convulsions, encephalitis, encephalopathy, Guillain-Barre syndrome, hypoesthesia, myelitis, multiple sclerosis, neuritis, neuropathy, optic neuritis, paralysis, paresis, transverse myelitis.
• Eye Disorders: Conjunctivitis, visual disturbances.
• Ear and Labyrinth Disorders: Earache, tinnitus.
• Cardiac Disorders: Palpitations, tachycardia.
• Vascular Disorders: Vasculitis.
• Respiratory, Thoracic, and Mediastinal Disorders: Bronchospasm, including asthma-like symptoms; dyspnea.
• Gastrointestinal Disorders: Dyspepsia.
• Hepatobiliary Disorders: Hepatitis, jaundice.
• Skin and Subcutaneous Tissue Disorders: Alopecia, angioedema, eczema, erythema multiforme, erythema nodosum, hyperhidrosis, lichen planus.
• Musculoskeletal and Connective Tissue Disorders: Arthritis, muscular weakness.
• General Disorders and Administration Site Conditions: Chills; immediate injection site pain, stinging, and burning sensation; injection site reaction; malaise.
• Investigations: Abnormal liver function tests.

Postmarketing Experience With Havrix And/Or Engerix-B

The following list includes adverse reactions for Havrix and/or Engerix-B not already reported above for Twinrix.

Eye Disorders: Keratitis.^a

• Skin and Subcutaneous Tissue Disorders: Stevens-Johnson syndrome.^a
• Congenital, Familial, and Genetic Disorders: Congenital abnormality.^b

^a Following Engerix-B.
^b Following Havrix.

Concomitant Administration With Vaccines And Immune Globulin

• Do not mix Twinrix with any other vaccine or product in the same syringe.
• When concomitant administration of immunoglobulin is required, it should be given with a different syringe and at a different injection site.
• There are no data to assess the concomitant use of Twinrix with other vaccines.

Immunosuppressive Therapies

• Immunosuppressive therapies, including irradiation, antimetabolites, alkylating agents, cytotoxic drugs, and corticosteroids (used in greater-than-physiologic doses), may reduce the immune response to Twinrix.

Interference With Laboratory Tests

• Hepatitis B surface antigen (HBsAg) derived from hepatitis B vaccines has been transiently detected in blood samples following vaccination. Serum HBsAg detection may not have diagnostic value within 28 days after receipt of a hepatitis B vaccine, including Twinrix.