Havrix is an immunization against Hepatitis A. The most common side effect is soreness and pain where the shot was given. Havrix has been linked to reports of severe side effects like high fevers, seizures, encephalopathy, SIRVA (shoulder injury), allergic reactions, and more.
How is Havrix given?
How many shots do I need?
Who should get Havrix?
Who should NOT get Havrix?
How long does it take for Havrix to work?
How long does Havrix protect me from Hepatitis A?
Havrix® is an immunization against a liver disease caused by the Hepatitis A virus (HAV). Havrix is approved for people who are 12 months and older. The vaccine is manufactured by GlaxoSmithKline and it was approved in the United States in 1995.
Havrix is administered by intramuscular injection. In young children, the shot is given in the thigh. In older children, teenagers, and adults, the shot is given in the upper arm muscle.
Two. They must be given 6 months apart.
Hepatitis A vaccination is recommended for all children when they are 12 months old. It is also recommended for people who are at high risk of infection and people at risk of complications, such as:
- People traveling or working in countries with high rates of Hepatitis A
- Men who have sex with men
- Users of illegal injection and non-injection drugs
- People who work in primate research laboratories
- People with chronic liver disease
- People with clotting-factor disorders
- Anyone who will have close contact with an adopted child from a country with a high rate of Hepatitis A
Havrix is contraindicated in people who had severe allergic reactions (e.g. anaphylaxis) after a previous dose of any vaccine against Hepatitis A, or to any other ingredient in Havrix (see below for a list).
Be aware that the tip cap of the pre-filled syringes contain latex, which could trigger allergic reactions in people who are hypersensitive.
Havrix starts to protect you from Hepatitis A within 2 weeks of the vaccine. It reaches maximum effectiveness by 4 weeks.
Fully-vaccinated adults should be protected from Hepatitis A for 25 years. Fully-vaccinated children should be protected for 14-20 years.
Children and teenagers between the ages of 12 months and 18 years old should get two 0.5-mL shots of Havrix. The second shot should be given between 6 months and 12 months after the first shot.
Doctors recommend that parents schedule their child’s first dose of the vaccine between the ages of 12 months and 23 months.
Adults over 18 years old who are not already immune to Hepatitis A should get two 1.0-mL shots of Havrix. The second shot should be given between 6 months and 12 months after the first shot.
The most common side effect of Havrix in adults and children over 2 years old was soreness where the shot was given (56% of adults and 12% of children). Less than 0.5% of soreness was severe. Headaches were reported by 14% of adults and less than 9% of children.
In studies of Havrix in children aged 11 months to 25 months old, the most common side effects were pain (32%), redness (29%), irritability (42%), drowsiness (28%), and loss of appetite (28%).
In children aged 15 months to 24 months, fevers over 100.6ºF occurred in 3% of children after the 1st dose and 3.3% after the 2nd dose. The risk of fever after the 1st dose of Havrix increased to 4.8% for children who were given the MMR+V vaccine at the same time.
Mild side effects linked to Havrix include:
- Abdominal pain
- Joint pain
- Loss of appetite
- Low fever
Severe side effects linked to Havrix include:
- Allergic reactions
- Birth defects
- Creatine phosphokinase increased
- Encephalopathy (brain inflammation)
- Enlarged lymph nodes
- Erythema multiforme
- Fever over 100ºF
- Flu-like symptoms
- Guillain-Barré Syndrome (GBS)
- Hepatitis (non-viral liver inflammation)
- Musculoskeletal stiffness
- Nerve damage (myelitis)
- Serum sickness-like syndrome
- Shoulder Injury Related to Vaccine Administration (SIRVA)
- Upper respiratory tract infection
- Vasovagal syncope (fainting)
Shoulder Injury Related to Vaccine Administration (SIRVA) is shoulder pain and limited range of motion in the arm where the shot was given. These symptoms are likely caused by accidentally injecting the vaccine into the bursa, tendons, or ligaments in the shoulder, which results in inflammation. SIRVA is not caused by nerve damage.
Each 1-mL adult dose of Havrix contains an inactivated viral antigen on 0.5-mg of aluminum (as aluminum hydroxide).
Each 0.5-mL pediatric dose of Havrix contains an inactivated viral antigen on 0.25-mg of aluminum (as aluminum hydroxide).
Havrix includes the following ingredients:
MRC-5 human diploid cells, formalin (not more than 0.1 mg/ mL), aluminum hydroxide, amino acid supplement (0.3% weight/volume), phosphate-buffered saline solution, polysorbate 20 (0.05 mg/ mL), neomycin sulfate (not more than 40 ng/mL), and aminoglycoside antibiotic included in the cell growth media.